Refrigerator and control method thereof

ABSTRACT

Provided are a refrigerator and a control method thereof. The refrigerator is characterized by enabling at least a part of a refrigerator door to be selectively transparent by a user&#39;s operation, such that the user sees through an inside of the refrigerator while the refrigerator door is closed.

TECHNICAL FIELD

A refrigerator and a control method thereof are disclosed herein.

BACKGROUND ART

Generally, a refrigerator is a home appliance which stores food at a lowtemperature in a storage space formed therein to be shielded by a door.To this end, the refrigerator is formed to cool an inside of the storagespace using cooling air generated through heat exchange with arefrigerant circulated in a refrigeration cycle, and thus to keep thestored food in an optimum state.

Recent refrigerators become bigger and have multi-functions according toa change in diet and a tendency toward high-quality of a product. Andthe refrigerators which have various structures and devices forconvenience to provide user convenience and also to enable internalspaces to be efficiently used have been released.

The storage space of the refrigerator may be opened and closed by thedoor. The refrigerator may be classified into various types according toan arrangement of the storage space and a structure of the door foropening and closing the storage space.

And a separate accommodation space which allows access from an outsidemay be provided at the door of the refrigerator. Thus, access to theaccommodation space may be allowed by opening an auxiliary door or ahome-bar door without opening of the entire refrigerator door.

Therefore, the food which is frequently used may be accommodated in theseparate accommodation space provided at the refrigerator door. Andsince the entire refrigerator door is not opened to accommodate thefood, a leak of the cooling air in the refrigerator may be minimized.

However, even in such a structure, there is a problem that the foodinside the refrigerator may not be checked without opening therefrigerator door. That is, to check whether desired food isaccommodated in the space inside refrigerator or in the separateaccommodation space provided at the door, the door should be opened. Andif there is not the desired food when the auxiliary door or the home-bardoor is opened, there is an inconvenience that a main door should beopened, and at this point, the cooling air may leak unnecessarily.

To solve the problems, a part of a front surface of the refrigeratordoor may be formed of a transparent material. However, in this case,there may be a problem in insulating an inside of the refrigerator. Andin the case in which the inside of the refrigerator may be seen througheven while not being used, the food is exposed to an outside, and thusthere may occur a problem in an external appearance.

DISCLOSURE OF INVENTION Technical Problem

The present invention is directed to a refrigerator which enables atleast a part of a refrigerator door to be selectively transparent by anuser's operation, such that the user may see through an inside of therefrigerator while the refrigerator door is closed, and a control methodthereof.

Also, the present invention is directed to a refrigerator in which atleast a part of a front surface of a refrigerator door is formed of halfglass, and a lighting unit in the refrigerator is turned on/off by auser's operation, and thus the user may selectively see through aninside of the refrigerator while the refrigerator door is closed, and acontrol method thereof.

Also, the present invention is directed to a refrigerator in which arefrigerator door may be selectively transparent by a knocking operationon a refrigerator door, and thus an inside of the refrigerator becomesvisible, and a control method thereof.

Also, the present invention is directed to a refrigerator which is ableto enhance recognition performance and reliability of an operation forselectively enabling an inside of the refrigerator to be visible througha panel assembly while a refrigerator door is closed, and a controlmethod thereof.

Also, the present invention is directed to a refrigerator having astructure which is provided at a refrigerator door, enables a use to seethrough an inside of the refrigerator even while the refrigerator dooris closed, and also insulates the refrigerator door.

Also, the present invention is directed to a refrigerator which enablesan inside of the refrigerator to be seen through while a lighting unitis turned on by a user's operation, and forms a mirror surface while thelighting unit is turned off, thereby forming an exterior of arefrigerator door.

Also, the present invention is directed to a refrigerator which preventsexposure of a detection device detecting an operation for enabling atleast a part of a refrigerator door to be selectively transparent, andexpands a see-through area.

Also, the present invention is directed to a refrigerator which allows afoaming solution to be smoothly filled into a perimeter surface of therefrigerator except a see-through area, and thus maintains insulationperformance.

Also, the present invention is directed to a refrigerator in which adetection device for detecting a user's operation is easily installedand assembled, and maintenance thereof is easily performed.

Also, the present invention is directed to a refrigerator which is ableto prevent dew condensation on a surface of a refrigerator door formedof a glass material and enabling an inside of the refrigerator to beseen through.

Also, the present invention is directed to a refrigerator in which asub-door is provided inside an opening part of a main door to minimize agap between the main door and the sub-door and also to preventinterference when the door is rotated.

Also, the present invention is directed to a refrigerator in which asub-door is easily opened and closed, and strength of an opening part isreinforced.

Also, the present invention is directed to a refrigerator which preventsa leak of cooling air due to random opening of a sub-door, and allows areliable operation.

Solution to Problem

According to an aspect of the present invention, there is provided arefrigerator including a cabinet configured to form a storage space; adoor configured to open and close the cabinet, and having an openingwhich is in communication with the storage space; a panel assemblyprovided at the opening, and having a half glass structure which allowsto selectively see through an inside of the refrigerator; a knockdetection device disposed to be in close contact with a rear surface ofthe panel assembly, and configured to detect a user's knocking operationon the panel assembly; and a lighting unit provided inside therefrigerator, and turned on or off by a signal of the knock detectiondevice while the door is closed, such that the panel assemblyselectively becomes transparent.

The refrigerator may further include a second detection device which isprovided at the rear surface of the panel assembly to emit light andthus to confirm a user's approach.

The lighting unit may be turned on when detecting signals of both of theknock detection device and the second detection device are input.

A bezel which does not transmit light may be formed at an edge of therear surface of the panel assembly, and the knock detection device maybe disposed at an area of the bezel.

The panel assembly may include a front panel which forms a front surfaceof the sub-door, and is formed in a half mirror which is selectivelytransparent by reflecting a part of light and transmitting another partof the light; a plurality of insulation panels which are spaced apartfrom the front panel, and formed of transparent tempered glass; and aspacer bar which is provided between the front panel and the insulationpanel and between the insulation panels, and spaces and seals betweenthe front panel and the insulation panel and between the insulationpanels.

The front panel may form an entire front surface of the door, and theinsulation panel may be formed to have a size smaller than the frontpanel, and formed at an internal area of the front panel.

The knock detection device may be disposed at an edge of the front panelwhich extends to an outside of the insulation panel.

According to another aspect of the present invention, there is provideda refrigerator including a cabinet configured to form a storage space; amain door configured to open and close the cabinet, and having anopening part which is in communication with the storage space; asub-door rotatably installed inside the opening part and configured toopen and close the opening part; a panel assembly configured to form afront surface of the sub-door, and formed of a half glass material; adetection device provided at the sub-door, and configured to detect auser's operation; and a lighting unit provided inside the refrigerator,and turned on or off by a signal of the detection device while thesub-door is closed, such that an inside of the opening part isselectively seen through the panel assembly.

The detection device may be a knock detection device which is in closecontact with a rear surface of the panel assembly and detects a user'sknocking operation on the panel assembly.

The knock detection device may include a microphone module which is incontact with the rear surface of the panel assembly and receives a soundgenerated by vibration transmitted through the panel assembly upon aknocking operation; an elastic member which presses the microphonemodule toward the panel assembly; and a support member in which theelastic member is accommodated, and which is installed and fixed to aninside of the sub-door.

The microphone module may include a microphone accommodation part whichis formed of an elastic material and accommodates a microphone, and anopening facing the panel assembly may be formed at the microphoneaccommodation part, and a protrusion which protrudes along acircumference of the opening and is in close contact with the panelassembly may be also formed.

The panel assembly may include a front panel which forms the frontsurface of the sub-door, and is formed in a half mirror which isselectively transparent by reflecting a part of light and transmittinganother part of the light; a plurality of insulation panels which arespaced apart from the front panel, and formed of transparent temperedglass; and a spacer bar which is provided between the front panel andthe insulation panel and between the insulation panels, and spaces andseals between the front panel and the insulation panel and between theinsulation panels.

A bezel which does not transmit light may be formed along an edge of thefront panel, and the knock detection device may be disposed at a rearsurface of the bezel.

A penetration part which transmits light at an area of the bezel may beformed at the front panel, and a second detection device which emits thelight, confirms a user's approach, and activates the knock detectiondevice may be further provided at the penetration part.

A detection device accommodation part which is recessed to accommodatethe knock detection device may be formed at a bottom surface of thesub-door, and the detection device accommodation part may be shielded byan accommodation part cover.

An injection port cover part which shields a foaming solution injectionport through which a foaming solution is injected to form an insulationat an inside of the sub-door may be formed at the accommodation partcover.

A knock PCB which processes a knock signal detected by the knockdetection device may be provided at the detection device accommodationpart.

A PCB installation part to which the knock PCB is installed and fixedmay be formed at the accommodation part cover.

A sub-hinge which protrudes laterally may be provided at an upper endand a lower end of the sub-door, and the sub-hinge may be inserted androtatably coupled into a hinge hole formed at the opening part.

The sub-hinge may include a door installation part which is installedand fixed to a corner of the upper end or the lower end of the sub-door;and a hinge coupling part which extends from the door installation partand passes through the hinge hole, and the hinge coupling part mayinclude a hinge shaft which is shaft-coupled at an inside of the maindoor; and a cut-away part which is recessed inward so that a part of thehinge hole is inserted when the sub-door is rotated.

A hinge installation part which is recessed so that the sub-hinge isinstalled therein may be formed at the upper end of the sub-door, and anelectric wire hole through which an electric wire connected to thedetection device passes may be formed at the hinge installation part.

A hinge cover which shields the sub-hinge from an upper side thereof,extends to an inside of the hinge hole, and forms a space between thehinge cover and the sub-hinge to guide the electric wire accommodatedtherein toward the main door may be provided at the hinge installationpart.

A side frame which is formed of a metallic material, extends verticallyand forms a side surface of the sub-door may be provided at thesub-door.

A hinge insertion part which is recessed inward so that the sub-hinge isinserted and installed therein may be formed at an upper end and a lowerend of the side frame.

The front panel may form an entire exterior of the front surface of thesub-door, and may be formed larger than the insulation panel.

A first side frame which forms one side surface of the sub-door andrestricts a sub-hinge rotatably supporting the sub-door at upper andlower ends of the sub-door, and a second side frame which forms anotherside surface of the sub-door facing the first side frame and has ahandle recessed inward may be installed at both ends of a rear surfaceof the insulation panel.

The first side frame and the second side frame may be formed of ametallic material, and a front bent part which is bent to be in contactwith a rear surface of the front panel and extends to the spacer bar maybe formed at the first side frame and the second side frame, and aheater installation groove in which a sub-door heater disposed along anedge of the front panel is accommodated may be formed at the front bentpart.

A bezel which is printed so as not to transmit light and formed to coverthe detection device, the front bent part and the sub-door heater may beformed along the edge of the front panel.

One end of the front panel at which the second side frame is installedmay be spaced apart from one end of the opening part, and the handle maybe recessed from an end of the front panel.

A front surface of the main door may be formed by an outer plate formedof a stainless material, and a multi-bent part which is bent to form aninclined surface along one end of the opening part may be formed at anend of the outer plate facing the handle.

A first injection port which is opened toward between the panel assemblyand the second side frame, and a second injection port which is openedto face the panel assembly may be formed at a lower end of the servedoor.

A foaming solution guide part which extends toward the second side framewith a curvature and guides a flow of a foaming solution may be formedat the first injection port.

The refrigerator may further include a door restricting member which isprovided at the sub-door and the main door which faces each other whilethe sub-door is closed, and restricts the sub-door from beingunintentionally opened by an inertial force when the main door isrotated.

The door restricting member may include a first magnet which isinstalled inside the main door to be in contact with the opening part;and a second magnet which is installed inside the sub-door to be locatedon an extension line of the first magnet while the sub-door is closed,and the first magnet and the second magnet may be disposed to generatean attraction.

The sub-door may include one pair of cap decorations which are formed ata front surface of the panel assembly, disposed at an upper side and alower side of the panel assembly, and forms an upper surface and a lowersurface of the sub-door; one pair of side frames which are attached toboth ends of a rear surface of the panel assembly and connect the pairof cap decorations so as to form a side surface of the sub-door; and adoor liner which forms a rear surface of the sub-door, and a foamingsolution may be filled in a space formed by the panel assembly, the capdecorations, the side frame and the sub-door liner, and may form aninsulation.

The pair of side frames may include a first side frame in which asub-hinge rotatably supporting the sub-door is coupled to an upper endand a lower end thereof; and a second side frame having a handle whichis recessed inward.

A gasket installation groove in which a sub-door gasket which is incontact with the main door to prevent a leak of cooling air is installedmay be formed at a rear surface of the door liner, and a vent hole whichdischarges air when the foaming solution is injected may be formed atthe gasket installation groove, and the vent hole may be covered whenthe sub-door gasket is installed in the gasket installation groove.

A plurality of vent holes may be arranged along the gasket installationgroove at regular intervals.

The vent hole may be formed at a first area which is the most distantfrom an injection port of the foaming solution for forming theinsulation, and a second area which is connected with the first area andat which the second side frame having the handle of the sub-door isdisposed.

According to still another aspect of the present invention, there isprovided a method of controlling a refrigerator in which a panelassembly which is formed of a half mirror material and installed at anopening part of a door in communication with an inside of therefrigerator is provided so as to selectively see through the inside therefrigerator, including activating a knock detection device whichdetects a user's knocking operation at an outside of the door while thedoor is closed; determining whether an input signal of the knockdetection device is valid; and turning on a lighting unit disposedinside the refrigerator by a main control part so as to see through theinside of the refrigerator when it is determined that the user'soperation is valid.

The knock detection device may be installed at a rear surface of thepanel assembly which forms an outer surface of the door, and may detecta sound of surface vibration of the panel assembly.

A detection device which detects a user's approach may be provided atthe door, and the main control part may turn on the lighting unit whenan input signal of the knock detection device is valid and the detectiondevice detects the user's approach.

A module PCB which is installed together with the knock detection deviceand processes a signal of the knock detection device may be provided atthe door, and the module PCB may determine whether a knock signal isvalid.

When the knock signal input from the knock detection device is detectedseveral times within a preset time, the knock signal may be determinedas a valid signal by the module PCB.

When the module PCB determines that the knock signal is valid, the validsignal may be transmitted to the main control part.

The main control part may turn off the lighting unit when a preset timepasses after the lighting unit is turned on.

The main control part may turn off the lighting unit when a valid signalis input again from the knock detection device after the lighting unitis turned on and a preset time passes.

The details of one or more implementations are set forth in theaccompanying drawings and the description below. Other features will beapparent from the description and drawings, and from the claims.

Advantageous Effects of Invention

The refrigerator and the control method thereof according to theproposed embodiment of the present invention have the following effects.

In the refrigerator according to the embodiment of the presentinvention, the panel assembly which selectively transmits or reflectsthe light is provided at a part of the door, and the lighting unit whichis turned on or off by the user's operation is provided inside the door,and the lighting unit can be turned on by the user's operation while thedoor is closed, and thus it is possible to see through the inside of therefrigerator.

Therefore, even while the door is not opened, the user can confirm thespace inside the refrigerator, and also can check the position of thefood, and thus the user convenience can be enhanced. Also, the door canbe prevented from being unnecessarily opened and closed, and loss of thecooling air can be prevented, and thus it is possible to improve powerconsumption and also to enhance storage performance.

And the panel assembly has a structure like a half glass which is seenthrough while the lighting unit is turned on, and functions as a mirrorwhile the lighting unit is not turned on, and thus an exterior of therefrigerator door can be enhanced.

And the microphone which detects a sound generated by the vibration uponthe user's knocking operation on the panel assembly can be provided atthe rear surface of the panel assembly. Therefore, the lighting unit canbe turned on or off by the user's knocking operation, and thus the panelassembly can be selectively transparent.

Therefore, since the panel assembly can become transparent by the simpleoperation, and the sound of the vibration transmitted through the samemedium is the same even though the user knocks on any positions of thefront surface of the panel assembly, the operation can be easilyperformed, and effectively detected.

Also, the microphone module having the built-in microphone of the knockdetection device is in close contact with the rear surface of the panelassembly, and thus a detection rate can be enhanced. At this point, thevibration or the sound wave having a certain wavelength generated uponthe knocking on the panel assembly is recognized as the valid signal,and thus the misrecognition due to an abnormal noise like the externalnoise is prevented.

And the detection device PCB which determines the knock signal isdisposed together with the knock detection device, and determines thevalid knock signal, and transmits a determined result to the maincontrol part inside the cabinet, and thus the efficiency and reliabilityin processing the signal can be enhanced by minimizing noise upon thedetermination of the knock signal. Also, when the signal input from theknock detection device is detected several times within the preset time,the signal is determined as the valid signal, and thus reliability ofthe operation can be further enhanced.

And the panel assembly includes the front panel formed of the halfmirror material, and the plurality of insulation panels formed of theinsulation glass, and thus thermal loss through the panel assembly canbe prevented. And the spacer bar and the sealant seals between the frontpanel and the insulation panel and between the plurality of insulationpanels, and thus an insulation space is formed, and the insulation spaceis in a vacuum state, or filled with an inert gas, and thus insulationperformance can be further enhanced.

And since the bezel is formed at the front panel, and the knockdetection device is located on the bezel, the knocking operation on thefront panel can be easily recognized, and the knock detection device isprevented from being exposed to an outside, and thus an exterior can befurther improved. Also, the detection device is formed at the bezelprovided at the lower end of the front panel, and thus the bezelprovided at another portion of the front panel can be relatively thin,and thus a see-through portion of the door can be widened.

And the foaming solution injection port for forming the insulation isformed at the lower end of the door, and the first foaming solutioninjection port is formed at a position of the second side frame having arelatively wide width so that the foaming solution can be directlyinjected toward the second side frame. And since a distance between thefirst side frame and the panel assembly is very narrow, and thus thefoaming solution may overflow, the second foaming solution injectionport is formed so that the foaming solution is injected toward an insidefurther than a position of the first side frame, i.e., the lower end ofthe panel assembly. Therefore, the foaming solution can be smoothlyinjected, and also can be prevented from being incompletely filled oroverflowing, and thus the insulation performance can be maintained.

And the side decoration which is in contact with the front plate isformed of the metallic material such as aluminum having high thermalconductivity. The heater installation part in which the sub-door heateris installed to be in contact with the outer end of the front plate isformed at the side decoration.

Therefore, the surface temperature of the front panel at the outerportion of the spacer bar which is vulnerable to dew condensation isincreased, and thus the dew condensation can be prevented. Also, sincethe front bent part is formed at the side decoration, and is in closecontact with the front panel, the dew condensation can be prevented frombeing generated along the perimeter of the front panel.

And since the knock detection device, the second detection device whichdetects the user's approach, and the detection device PCB areaccommodated and installed at the detection device accommodation partformed to be recessed at the lower end of the door, installation,assembling and maintenance of the detection device can be easilyperformed.

And the sub-door which can be seen through is accommodated inside theopening part of the main door, and the upper hinge and the lower hingeextend laterally, and pass through the hinge hole of the opening part,and are rotatably installed therein.

Therefore, an interference space due to the upper hinge and the lowerhinge can be prevented, and the sagging of the sub-door can also beprevented, and a gap between the opening part of the main door and thesub-door can be minimized, and thus the external appearance can beenhanced. Also, the side supporter which supports the upper hinge andthe lower hinge is formed of the metallic material, coupled to the upperhinge and the lower hinge so that the installation position thereof ismaintained, and thus the interference with the opening part due todeformation of the sub-door can be prevented.

The side supporter formed of the metallic material serves to maintain ashape of the sub-door at both ends of the sub-door, and also enhancesthe strength of the sub-door.

And the magnet is provided at a position at which the main door facesthe sub-door, and the attraction is formed between the main door and thesub-door, and thus while the sub-door is closed, the sub-door can bemaintained in the closed state by the magnetic force.

Therefore, the sub-door can be prevented from being unintentionallyopened due to a shock generated when the main door is closed and openedor an inertial force generated when the main door is rotated, and alsoloss of the cooling air and an increase in the power consumption can beprevented.

Even though all the elements of the embodiments are coupled into one oroperated in the combined state, the present disclosure is not limited tosuch an embodiment. That is, all the elements may be selectivelycombined with each other without departing from the scope of theinvention. Furthermore, when it is described that one comprises (orincludes or has) some elements, it should be understood that it maycomprise (or include or have) only those elements, or it may comprise(or include or have) other elements as well as those elements if thereis no specific limitation. Unless otherwise specifically defined herein,all terms comprising technical or scientific terms are to be givenmeanings understood by those skilled in the art. Like terms defined indictionaries, generally used terms needs to be construed as meaning usedin technical contexts and are not construed as ideal or excessivelyformal meanings unless otherwise clearly defined herein.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it will be understood by those skilledin the art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the invention as definedby the appended claims. Therefore, the preferred embodiments should beconsidered in a descriptive sense only and not for purposes oflimitation, and also the technical scope of the invention is not limitedto the embodiments. Furthermore, the present invention is defined not bythe detailed description of the invention but by the appended claims,and all differences within the scope will be construed as beingcomprised in the present disclosure.

BRIEF DESCRIPTION OF DRAWINGS

Embodiments will be described in detail with reference to the followingdrawings in which like reference numerals refer to like elements, andwherein:

FIG. 1 is a perspective view of a refrigerator according to anembodiment of the present invention;

FIG. 2 is a front view illustrating a state in which all doors of therefrigerator are opened;

FIG. 3 is a perspective view illustrating a state in which a sub-door ofthe refrigerator is opened;

FIG. 4 is a front view illustrating a state in which the sub-door isopaque;

FIG. 5 is a front view illustrating a state in which the sub-door istransparent;

FIG. 6 is a perspective view illustrating a state in which a main doorand the sub-door of the refrigerator are coupled to each other;

FIG. 7 is an exploded perspective view illustrating a state in which themain door and the sub-door are separated;

FIG. 8 is an exploded perspective view of the main door;

FIG. 9 is an exploded perspective view of the main door and a displayunit;

FIGS. 10A and 10B are partial perspective views illustrating aninstalling state of the display unit;

FIG. 11 is a cross-sectional view illustrating an installed state of thedisplay unit;

FIG. 12 is an exploded perspective view of a display assembly;

FIG. 13 is a cross-sectional view taken along line 13-13′ of FIG. 1;

FIG. 14 is an exploded perspective view of an installation structure ofa door opening device according to the embodiment of the presentinvention;

FIG. 15 is a view illustrating an operation state of the door openingdevice;

FIG. 16 is a cross-sectional view taken along line 16-16′ of FIG. 1;

FIG. 17 is a perspective view of the sub-door;

FIG. 18 is an exploded perspective view of the sub-door when being seenfrom a front;

FIG. 19 is an exploded perspective view of the sub-door when being seenfrom a rear;

FIG. 20 is a cut-away perspective view taken along line 20-20′ of FIG.17;

FIG. 21 is an exploded perspective view of a panel assembly according tothe embodiment of the present invention;

FIG. 22 is a cross-sectional view schematically illustrating an exampleof a front panel of the panel assembly;

FIG. 23 is a cross-sectional view schematically illustrating anotherexample of the front panel of the panel assembly;

FIG. 24 is a cross-sectional view schematically illustrating stillanother example of the front panel of the panel assembly;

FIG. 25 is a cross-sectional view of the sub-door;

FIG. 26 is an exploded perspective view illustrating a couplingstructure of the sub-door and an upper hinge;

FIG. 27 is a partial perspective view illustrating an installed state ofthe upper hinge;

FIG. 28 is a longitudinal cross-sectional view illustrating a couplingstructure of the upper hinge;

FIG. 29 is a longitudinal cross-sectional view illustrating a couplingstructure of the sub-door and a lower hinge;

FIG. 30 is an exploded perspective view illustrating a couplingstructure of a knock detection device and a second detection device ofthe sub-door when being seen from a front;

FIG. 31 is an exploded perspective view illustrating a couplingstructure of the knock detection device and the second detection deviceof the sub-door when being seen from a lower side;

FIG. 32 is an exploded perspective view of the knock detection device;

FIG. 33 is a cross-sectional view taken along line 33-33′ of FIG. 17;

FIG. 34 is a cross-sectional view of a microphone module of the knockdetection device;

FIG. 35 is an exploded perspective view illustrating a couplingstructure of the second detection device;

FIG. 36 is a partial perspective view illustrating an installed state ofthe second detection device;

FIG. 37 is a view illustrating an electric wire arrangement inside thesub-door;

FIG. 38 is a perspective view illustrating a state in which a foamingsolution is injected into the sub-door;

FIG. 39 is a view illustrating an arrangement of a vent hole of thesub-door;

FIG. 40 is a perspective view illustrating an operation state of aprojector of the refrigerator;

FIG. 41 is a cut-away perspective view illustrating an internalstructure of a freezer compartment of the refrigerator;

FIG. 42 is a block diagram illustrating a flow of a control signal ofthe refrigerator;

FIG. 43 is a flowchart sequentially illustrating an operation of thesub-door of the refrigerator;

FIG. 44 is a perspective view illustrating an installed state of thedisplay unit;

FIG. 45 is a view illustrating a configuration of a front surface of thedisplay unit;

FIG. 46 is a view illustrating a change in a display state of thedisplay unit according to a knocking operation;

FIG. 47 is a view illustrating the change in the display state when thesub-door is opened and closed;

FIG. 48 is a view illustrating the change in the display state of thedisplay unit when an auto-door function is set;

FIG. 49 is a view illustrating the change in the display state of thedisplay unit when an auto-drawer function is set; and

FIG. 50 is a view illustrating the change in the display state of thedisplay unit when a temperature fixing function is set.

MODE FOR THE INVENTION

Hereinafter, exemplary embodiments of the present invention will bedescribed in detail with reference to the accompanying drawings.However, The invention may, however, be embodied in many different formsand should not be construed as being limited to the embodiments setforth herein; rather, alternative embodiments included in otherretrogressive inventions or falling within the spirit and scope of thepresent disclosure can easily be derived through adding, altering, andremoving, and will fully convey the concept of the invention to thoseskilled in the art.

FIG. 1 is a perspective view of a refrigerator according to anembodiment of the present invention. And FIG. 2 is a front viewillustrating a state in which all doors of the refrigerator are opened.And FIG. 3 is a perspective view illustrating a state in which asub-door of the refrigerator is opened.

As illustrated in the drawings, an external appearance of a refrigerator1 according to an embodiment of the present invention may be formed by acabinet 10 which forms a storage space and a door which opens and closesthe storage space.

An inside of the cabinet 10 may be divided up and down by a barrier 11,and a refrigerator compartment 12 may be formed at an upper portion ofthe cabinet 10, and a freezer compartment 13 may be formed at a lowerportion of the cabinet 10. And various accommodation members 121 such asa shelf, a drawer and a basket may be provided inside the refrigeratorcompartment 12. If necessary, the accommodation members 121 may beinserted and withdrawn while the door is opened, and may accommodate andstore food by the inserting and withdrawing.

A main lighting unit 85 which illuminates the refrigerator compartment12 may be provided at the refrigerator compartment 12. The main lightingunit 85 may also be disposed at the freezer compartment 13, and may alsobe disposed at any positions of an inner wall surface of therefrigerator 1.

A drawer type freezer compartment accommodation member 131 which isinserted and withdrawn may be mainly disposed inside the freezercompartment 13. The freezer compartment accommodation member 131 may beformed to be inserted and withdrawn, interlocking with opening of afreezer compartment door 30. And a first detection device 31 whichdetects a user's body may be provided at a front surface of the freezercompartment door 30. Detailed description of the first detection device31 will be described again below.

The door may include a refrigerator compartment door 20 and the freezercompartment door 30. The refrigerator compartment door 20 serves to openand close an opened front surface of the refrigerator compartment 12 byrotation, and the freezer compartment door 30 serves to open and closean opened front surface of the freezer compartment 13 by rotation. Andone pair of refrigerator compartment doors 20 and one pair of freezercompartment doors 30 may be provided left and right to shield therefrigerator compartment 12 and the freezer compartment 13,respectively.

A plurality of door baskets may be provided at the refrigeratorcompartment door 20 and the freezer compartment door 30. The doorbaskets may be provided so as not to interfere with the accommodationmembers 121 and 131 while the refrigerator compartment door 20 and thefreezer compartment door 30 are closed.

The refrigerator compartment door 20 and the freezer compartment door 30forms an entire exterior when being seen from a front. And the exteriorof each of the refrigerator compartment door 20 and the freezercompartment door 30 may be formed of a metallic material, and the entirerefrigerator 1 may have a metallic texture. And if necessary, adispenser which dispenses water or ice may be provided at therefrigerator compartment door 20.

Meanwhile, the embodiment of the present invention describes an examplein which a French type door opening and closing one space by rotatingone pair of doors is applied to a bottom freezer type refrigeratorhaving the freezer compartment provided at a lower side thereof.However, the present invention may be applied to all types ofrefrigerators having the door.

Meanwhile, a right one (in FIG. 1) of the pair of refrigeratorcompartment doors 20 may be formed to be doubly opened and closed.Specifically, the right refrigerator compartment door 20 may include amain door 40 which is formed of the metallic material to open and closethe refrigerator compartment 12, and a sub-door 50 which is rotatablydisposed inside the main door 40 to open and close an opening of themain door 40.

The main door 40 may be formed to have the same size as that of a leftone (in FIG. 1) of the pair of refrigerator compartment doors 20, may berotatably installed at the cabinet 10 by a main hinge 401 and a middlehinge 402, and thus may open and close a part of the refrigeratorcompartment 12.

And an opening part 403 is formed at the main door 40. A door basket 404is installed at a rear surface of the main door 40 including an insideof the opening part 403. Therefore, a user may have access to the doorbasket 404 through the opening part 403 without opening of the main door40. At this point, a size of the opening part 403 may correspond to mostof a front surface of the main door 40 except a part of a perimeter ofthe main door 40.

The sub-door 50 is rotatably installed inside the opening part 403, andopens and closes the opening part 403. And at least a part of thesub-door 50 is formed of a transparent material like glass. Therefore,access to the opening part 403 is allowed through opening of thesub-door 50, and even while the sub-door 50 is closed, it is alsopossible to see through the inside of the opening part 403. The sub-door50 may be referred to as a see-through door.

Meanwhile, the glass material forming the sub-door 50 may be formed tobe selectively changed into a transparent or opaque state by controllinga light transmittance and a reflectivity thereof according to a user'soperation. Therefore, the glass material becomes transparent so that aninside of the refrigerator 1 is visible, only when the user wants, andotherwise, is maintained in the opaque state.

FIG. 4 is a front view illustrating a state in which the sub-door isopaque.

As illustrated in the drawing, when there are not any operations in therefrigerator 1 while all of the main door 40 and the sub-door 50 areclosed, the sub-door 50 may have an opaque black color or may be in astate like a mirror surface. Therefore, the sub-door 50 may not enablean internal space of the sub-door 50, i.e., an accommodation space ofthe main door 40 and an internal space of the refrigerator compartment12 to be visible.

Therefore, the sub-door 50 may be maintained in a state having the blackcolor, and thus may provide a beautiful and simple exterior having amirror-like texture to the refrigerator 1. Also, the exterior mayharmonize with the metallic texture of the main door 40, therefrigerator compartment door 20 and the freezer compartment door 30,and thus may provide a more luxurious image.

FIG. 5 is a front view illustrating a state in which the sub-door istransparent.

As illustrated in the drawing, in a state in which all of the main door40 and the sub-door 50 are closed, the sub-door 50 may be transparent bya user's certain operation. When the sub-door 50 is in the transparentstate, the accommodation space of the main door 40 and the internalspace of the refrigerator compartment 12 may be visible. Therefore, theuser may confirm an accommodation state of food in the accommodationspace of the main door 40 and the internal space of the refrigeratorcompartment 12 without opening of the main door 40 and the sub-door 50.

Also, when the sub-door 50 is in the transparent state, a display unit60 disposed at a rear of the sub-door 50 is in a visible state, and anoperation state of the refrigerator 1 may be displayed to an outside.

A specific operating method and configuration for enabling theaccommodation space of the main door 40 and the internal space of therefrigerator compartment 12 to be visible will be described below indetail.

FIG. 6 is a perspective view illustrating a state in which the main doorand the sub-door of the refrigerator arc coupled to each other. And FIG.7 is an exploded perspective view illustrating a state in which the maindoor and the sub-door are separated. And FIG. 8 is an explodedperspective view of the main door.

As illustrated in the drawings, an external appearance of the main door40 may be formed by an outer plate 41 which is formed of a metallicmaterial, a door liner 42 which is coupled to the outer plate 41, anddoor cap decorations 45 and 46 which are provided at upper and lowerends of the outer plate 41 and the door liner 42.

The outer plate 41 may be formed of a plate-shaped stainless material,and may be formed to be bent and thus to form a part of a front surfaceand a perimeter surface of the main door 40.

The door liner 42 may be injection-molded with a plastic material, andforms the rear surface of the main door 40. And the door liner 42 mayalso be formed so that an area thereof corresponding to the opening part403 is opened. The opening part 403 may have a plurality of unevenstructures so that the door basket 404 is installed.

A rear gasket 44 may be provided at a perimeter of a rear surface of thedoor liner 42. The rear gasket 44 is in close contact with a perimeterof the cabinet 10, and prevents a leak of cooling air between the maindoor 40 and the cabinet 10.

And a door lighting unit 49 which illuminates the inside of the openingpart 403 may be provided at an upper surface of the door liner 42. Thedoor lighting unit 49 may emit light downward from an upper side of theopening part 403, and thus may illuminate the entire opening part 403including the door basket 404, and may also enable the sub-door 50 to bein the transparent state.

The cap decorations 45 and 46 form an upper surface and a lower surfaceof the main door 40, and a hinge installation part 451 which enables themain door 40 to be rotatably installed at the cabinet 10 may be formedat each of the cap decorations 45 and 46. An upper end of the main door40 may be coupled to the main hinge 401, and a lower end of the maindoor 40 may be coupled to the middle hinge 402, and thus the upper andlower ends of the main door 40 may be rotatably supported.

And a door handle 462 may be formed to be recessed from the lowersurface of the main door 40, i.e., the cap decoration 46. The user mayput a hand into the door handle 462, may rotate the main door 40, andthus may open and close the refrigerator compartment 12.

Meanwhile, a door frame 43 may be further provided between the outerplate 41 and the door liner 42. The door frame 43 may be coupled betweenthe outer plate 41 and the door liner 42, and may form a perimeter ofthe opening part 403.

In a state in which the outer plate 41, the door liner 42, the doorframe 43, and the cap decorations 45 and 46 are coupled with each other,a foaming solution may be filled inside an internal space of the maindoor 40, and thus an insulation may be formed therein. That is, theinsulation may be disposed at a perimeter area of the opening part 403,and thus isolate a space inside the refrigerator 1 from a space outsidethe refrigerator 1.

The door frame 43 may be injection-molded with a plastic material whichis different from that of the door linier 42. If necessary, the doorframe 43 may be integrally formed with the door liner 42, and may bedirectly coupled to the outer plate 41.

A frame stepped part 431 which protrudes inward may be formed at aninner surface of the door frame 43. Therefore, when the sub-door 50 isclosed, the frame stepped part 431 may support the sub-door 50.

A front gasket 434 may be provided at the frame stepped part 431. Thefront gasket 434 is in contact with a rear surface of the sub-door 50when the sub-door 50 is closed, and thus seals between the main door 40and the sub-door 50. Of course, the front gasket 434 may be omitted, ifnecessary. Also, the front gasket 434 may be formed in a sheet shapeformed of a metallic material, and may also be formed to be in closecontact with a sub-door gasket 591 having a magnetic force by themagnetic force.

A frame heater 4321 may be provided at a rear surface of the framestepped part 431. The frame heater 4321 is disposed along the framestepped part 431, and heats the frame stepped part 431. The framestepped part 431 may have a relatively low surface temperature due to aninfluence of cooling air in the refrigerator 1. Therefore, dewcondensation may occur on a surface of the frame stepped part 431. Thedew condensation may be prevented by driving of the frame heater 4321.

A hinge hole 433 in which each of sub-hinges 51 and 52 for installingthe sub-door 50 is installed is formed at each of both sides of the doorframe 43. The hinge hole 433 is formed at a position which faces a sidesurface of the sub-door 50, and also formed so that each of thesub-hinges 51 and 52 is inserted therein.

Meanwhile, a hinge case 47 may be provided at the inner surface of thedoor frame 43 (which is in contact with the insulation) corresponding tothe hinge hole 433. The hinge case 47 is formed by vertically coupling afirst case 471 and a second case 472 to each other. The hinge case 47forms a space which rotatably accommodates a part of each of thesub-hinges 51 and 52 inserted through the hinge hole 433 when the firstcase 471 and the second case 472 are coupled to each other.

A hinge installation member 473 is provided at a recessed space of thehinge case 47. The hinge installation member 473 may be fixed by thecoupling of the first case 471 and the second case 472. The hingeinstallation member 473 may be formed of a steel material, and may havea shaft insertion part 4731 in which a hinge shaft of each of thesub-hinges 51 and 52 is inserted.

The hinge case 47 may be installed at the hinge hole 433 which is formedat each of upper and lower portions of the door frame 43. And the hingecases 47 which are disposed up and down may be formed to have the samestructure and shape.

Meanwhile, a hinge frame 48 may be provided at an outside of the doorframe 43. The hinge frame 48 is formed to vertically extend, and fixesthe hinge cases 47 which are disposed up and down.

Specifically, the hinge frame 48 may be formed of a metallic material ora plastic material having excellent strength, may be formed in a plateshape, and may be formed to vertically extend. An upper end 482 and alower end 483 of the hinge frame 48 may be bent, and then may be coupledand fixed to the cap decorations 45 and 46 provided at the upper andlower ends of the main door 40. That is, the upper end 482 and the lowerend 483 of the hinge frame 48 are fixed to the cap decorations 45 and46, and thus an installation position thereof may be maintained, andalso the hinge frame 48 indirectly supports the sub-hinges 51 and 52.

A case fixing part 481 may be formed at each of upper and lower portionsof the hinge frame 48. The case fixing part 481 may be formed by cuttingaway a part of the hinge frame 48. Therefore, a portion of the hingecase 47 which forms the recessed space may be accommodated and fixedinto the cut-away case fixing part 481 of the hinge frame 48. At thispoint, the hinge case 47 may be coupled to the hinge frame 48 by aseparate fastening member such as a screw.

A frame reinforcing part 484 may be formed between the case fixing parts481, which are formed at the upper and lower portions of the hinge frame48, to be recessed. And a plurality of frame openings 485 may be formedat the frame reinforcing part 484. The frame reinforcing part 484 mayreinforce strength of the hinge frame 48, may prevent the hinge frame 48from being bent or deformed, and may also maintain an installationposition of the hinge case 47.

And when the foaming solution is injected into the main door 40, asurface area is increased, and thus adhesion with the foaming solutionis enhanced. Also, the foaming solution may pass through the frameopenings 485, and thus flowability of the foaming solution may beimproved. When the insulation is molded, the hinge frame 48 may beburied and fixed in the insulation.

The sub-hinges 51 and 52 may include an upper hinge 51 which isinstalled at an upper end of the sub-door 50 and a lower hinge 52 whichis installed at a lower end of the sub-door 50. And the upper hinge 51and the lower hinge 52 may extend laterally toward the hinge hole 433,and may be coupled at an inside of the main door 40.

Therefore, the sub-hinges 51 and 52 may be installed at accuratepositions, and may have a structure which extends laterally.Accordingly, since there is not an interfering structure with thesub-hinges 51 and 52 at a gap between the main door 40 and the sub-door50, a distance between the main door 40 and the sub-door 50 may bemaintained in a very narrow state, and the exterior may be furtherenhanced. Also, since the distance between the main door 40 and thesub-door 50 is maintained in the very narrow state, and deflection ofthe sub-door 50 is effectively prevented, the interference with the maindoor 40 upon the rotation of the sub-door 50 may be prevented.

And a hinge cover 53 which shields the upper hinge 51 and guides accessof an electric wire of the sub-door 50 may be further provided at anupper side of the upper hinge 51.

FIG. 9 is an exploded perspective view of the main door and the displayunit. And FIGS. 10A and 10B are partial perspective views illustratingan installing state of the display unit.

As illustrated in the drawings, the display unit 60 may be provided atthe opening part 403 of the main door 40. The display unit 60 serves todisplay an operation state of the refrigerator 1 and also to operate therefrigerator 1, and is formed so that the user recognizes through thesub-door 50 from an outside when the sub-door 50 is in the transparentstate. That is, the display unit 60 is not visible from the outsidewhile the sub-door 50 is in the opaque state, but may indicate a varietyto information to the outside while the sub-door 50 is in thetransparent state.

Or course, the display unit 60 may include a display 61 which displaysstate information of the refrigerator 1, and various operating buttons62 which set the operation of the refrigerator 1. The operation of therefrigerator 1 may be operated by the operating buttons 62.

The display unit 60 may be separably provided at a lower end of theopening part 403. Therefore, when it is necessary to check or repair thedisplay unit 60, the display unit 60 may be separated. And after themain door 40 is assembled, the display unit 60 which is assembled as aseparate module may be simply installed. Also, the display unit 60 whichhas a necessary function according to a specification of therefrigerator 1 may be selectively installed.

To install and separate the display unit 60, a display installingprotrusion 435 is formed at both inner side surfaces of the opening part403. And a display connection part 436 for electrical connection withthe display unit 60 may be provided at the lower end of the opening part403.

The display installing protrusion 435 may be formed by protruding a sidesurface of the opening part 403, more specifically, a part of the doorliner 42 and a part of the door frame 43. That is, the displayinstalling protrusion 435 is formed by coupling a liner sideinstallation part 4352 and a frame side installation part 4351 to eachother, and may be formed in a protrusion shape having a circular crosssection. Therefore, when the display unit 60 is installed, the displayinstalling protrusion 435 is maintained in an installed state, and thuscoupling between the door liner 42 and the door frame 43 may be morefirmly maintained. A plurality of display installing protrusions 435 maybe formed and may be arranged vertically.

The display installing protrusion 435 has a structure which is matchedwith a display guide 634 formed at both of left and right side surfacesof the display unit 60. The display guide 634 has a structure which isopened downward. Therefore, when the display unit 60 is moved downwardfrom an upper side, the display installing protrusion 435 and thedisplay guide 634 are coupled to each other. And in a state in which thedisplay unit 60 is installed, the display unit 60 may be seated andfixed to the lower end of the opening part 403.

The display connection part 436 may be formed at a bottom surface of thedoor liner 42. The display connection part 436 may be formed to berecessed or stepped downward, and may be formed so that at least a partof the display unit 60 is inserted therein when the display unit 60 isinstalled.

And a door connector 4361 may be provided at the display connection part436. The door connector 4361 may be connected with an electric wirewhich supplies electric power for an operation of the display unit 60and transmits a signal, and may be electrically connected with thedisplay unit 60 by a separable structure of the display 61.

That is, the door connector 4361 protrudes upward from a bottom surfaceof the display connection part 436, and may be coupled and electricallyconnected to a display connector 651 provided at a bottom of the displayunit 60 when the display unit 60 is installed.

A plurality of door connectors 4361 may be provided, and may be formedseparately according to functions of the display unit 60. That is, thedoor connectors 4361 may be independently formed corresponding to thedisplay 61 and the operating buttons 62 of the display unit 60, and mayalso be formed so that the separate electric power and signal aretransmitted to each of them.

Meanwhile, a case extension part 635 is formed at a lower end of a rearsurface of the display unit 60. And a screw hole 6351 in which a screwis fastened is formed at the case extension part 635, and thus thedisplay unit 60 may be maintained in a coupled state to the main door40.

FIG. 11 is a cross-sectional view illustrating an installed state of thedisplay unit. And FIG. 12 is an exploded perspective view of a displayassembly.

As illustrated in the drawings, the display unit 60 may include an outercase 63 which forms an external appearance, an inner case 64 which isprovided inside the outer case 63, a display PCB 65 and a display cover66.

The outer case 63 forms an entire exterior of the display unit 60, andhas an accommodation space formed therein to accommodate the inner case64.

The accommodation space is opened forward, and a connector opening 631for coupling to the door connector 4361, through which the electric wireconnected to the display connector 651 passes, may be formed at a bottomsurface of the accommodation space. The display connector 651 may beprovided at a lower side of the connector opening 631, and if necessary,the display connector 651 may be fixed to the connector opening 631.

Therefore, when the display unit 60 is installed at the opening part 403of the main door 40, the display connector 651 and the door connector4361 may be coupled and connected to each other by moving the displayunit 60 up and down. By such a connection, the power supplying and thesignal transmitting to the display unit 60 may be enabled.

A plurality of case coupling protrusions 632 which protrude to becoupled to the inner case 64 are formed at inner upper and lower ends ofthe accommodation space. The case coupling protrusions 632 may be formedat an opened entrance side of the accommodation space, and may be formedat regular intervals.

A case support part 633 which supports the inner case 64 is formed toprotrude inward from both of left and right sides of an inner surface ofthe accommodation space. A screw hole 6331 in which a screw is insertedmay be further formed at the case support part 633, and the inner case64 may be installed and fixed to the case support part 633.

The display guide 634 is formed at both of left and right side surfacesof the outer case 63. The display guide 634 may be formed in a rib shapewhich protrudes from both of the left and right side surfaces of theouter case 63. And the display guide 634 is formed to be openeddownward, and the display installing protrusion 435 may be insertedthrough an opened lower side thereof.

The display guide 634 is formed so that a width thereof becomes narrowerupward from an opened entrance 6343 thereof. An upper end 6341 of thedisplay guide 634 may be formed to have the same size as a diameter ofthe display installing protrusion 435. Therefore, the display installingprotrusion 435 may be easily inserted into the display guide 634, andmay be restricted by the upper end 6341 of the display guide 634.

Also, a fixing part 6342 which protrudes inward is further formed at thedisplay guide 634. A distance between the fixing parts 6342 may beformed somewhat smaller than the diameter of the display installingprotrusion 435. Therefore, the display guide 634 may be elasticallydeformed while passing through the fixing part 6342, and may be fittedand fixed when being moved to the upper end 6341 of the display guide634.

The inner case 64 may be injection-molded with a plastic material, andmay provide a space in which the display PCB 65 is installed. A centerof the inner case 64 is formed to be recessed with a size correspondingto the display PCB 65, and a plurality of case coupling grooves 641 areformed at a perimeter of the inner case 64, and the case couplingprotrusion 632 is coupled therein.

A case seating part 642 which extends laterally and is seated on thecase support part 633 is formed at both side surfaces of the inner case64. The inner case 64 is coupled to the outer case 63 by a screwfastened into a screw hole 6421 of the case seating part 642.

A case hole 643 is formed at one side surface of the inner case 64. Thecase hole 643 serves as a passage of the electric wires connected to thedisplay PCB 65, and the electric wires may pass through the case hole643, and may be connected to the display connector 651 through theconnector opening 631.

The display PCB 65 may be accommodated in a space formed inside theinner case 64. The display 61 and the plurality of operating buttons 62may be installed at the display PCB in the form of a module. Andelements on the display PCB 65 may be covered and sealed with a resinmaterial for waterproofing and moisture-proofing.

The display 61 may be formed in a panel type which displays theoperation state and operation information of the refrigerator 1. And theplurality of operating buttons 62 may be provided at both of left andright sides of the display 61, and may be formed to be operated by auser's operation which pushes the display cover 66.

While the display PCB 65 is installed at the inner case 64, the innercase 64 is accommodated inside the outer case 63, and the display 61 iscoupled so as to shield an opening of the outer case 63. Therefore, thedisplay PCB 65 and the inner case 64 may be shielded by the display 61.

The display cover 66 may be formed to have a size corresponding to anopened front surface of the outer case 63. Therefore, the display cover66 may form an exterior of a front surface of the display unit 60. And acenter of the display cover 66 is formed so that information output fromthe display 61 is projected therethrough. The display 61 may be exposedthrough an opening of the display cover 66, or may be exposed to anoutside by forming a part of the display cover 66 to be transparent.

The plurality of operating buttons 62 may be provided at both of theleft and right sides of the display 61. The plurality of operatingbuttons 62 may also be correspondingly indicated on both sides of thedisplay cover 66. The operating buttons 62 indicated on the displaycover 66 are not actual operating buttons 62, but are indicated atcorresponding positions, and may be touched or pushed by the user.

A case fixing member 661 which installs and fixes the display cover 66is formed to protrude from both of left and right side ends of thedisplay cover 66. An end of the case fixing member 661 may be formed ina hook shape, and may be hooked and restricted by a case restrictinggroove 636 formed at both side surfaces of the outer case 63, and thusthe display cover 66 may be installed and fixed.

FIG. 13 is a cross-sectional view taken along line 13-13′ of FIG. 1.

As illustrated in the drawing, the door lighting unit 49 may be providedat an upper portion of the main door 40. The door lighting unit 49 maybe formed at a space between the door liner 42 and the door frame 43. Ofcourse, an installation position of the door lighting unit 49 is notlimited, and may be formed at one of the door liner 42 and the doorframe 43, and may be disposed at a position which illuminates the insideof the opening part 403.

The door lighting unit 49 may include a lamp case 491 which is installedinside the main door 40, a lamp PCB 492 which is provided at one side ofthe lamp case 491 and at which a plurality of LEDs 4921 are disposed,and a lamp cover 493 which shields an opened surface of the lamp case491 and is exposed through the opening part 403.

The lamp cover 493 is formed to extend long along the door liner 42, andincludes a recessed part 4914 which forms a recess space therein toaccommodate the lamp PCB 492. Specifically, a surface of the recessedpart 4914 which faces the lamp PCB 492 may be formed to be rounded, andlight emitted from the lamp PCB 492 is reflected by a rounded surface4915 having a predetermined curvature, and directed to the lamp case491. A film which increases the reflectivity of the light may beattached to or coated on an inner surface of the recessed part 4914,particularly, the rounded surface 4915.

A lamp PCB installation part 4913 at which the lamp PCB 492 is installedis formed at one surface which faces the rounded surface 4915. The lampPCB installation part 4913 enables the lamp PCB 492 to be installed andfixed in a direction perpendicular to the lamp cover 493. At this point,the lamp PCB installation part 4913 and the lamp PCB 492 are locatedabove the door frame 43 so as to be covered by an end of the door frame43 when being seen from a lower side. Therefore, the LEDs 4921 may becovered by the end of the door frame 43 without an additional bezel, andthus a phenomenon in which the light looks as if forming a lump may beprevented.

A first case installation part 4911 and a second case installation part4912 are formed at both ends of the recessed part 4914. The first caseinstallation part 4911 and the second case installation part 4912 areinstalled to be in surface contact with inner side surfaces of the doorliner 42 and the door frame 43, respectively, and thus the lamp case 491may be hooked and restricted or adhered inside the main door 40.

And cover insertion grooves 4916 and 4917 may be formed at the firstcase installation part 4911 and the second case installation part 4912.The cover insertion grooves 4916 and 4917 may be formed to be stepped,and thus a space in which both ends of the lamp cover 493 are insertedwhen the lamp case 491 is installed may be formed between the first caseinstallation part 4911 and the door liner 42 and between the second caseinstallation part 4912 and the door frame 43.

The lamp cover 493 is formed so that the light reflected by the roundedsurface 4915 of the recessed part 4914 is transmitted therethrough. Thelamp cover 493 serves to shield an opening of the recessed part 4914 andalso to shield a space between the door liner 42 and the door frame 43.

The lamp cover 493 is formed to be transparent or translucent, such thatthe light reflected by the rounded surface 4915 and uniformly spread istransmitted therethrough. Therefore, the light passing through the lampcover 493 illuminates the inside of the refrigerator 1 in an indirectillumination method, and have an effect like surface emitting.

To effectively diffuse the light, a film may be attached to or coated onthe lamp cover 493. And if necessary, when the lamp cover 493 isinjection-molded, particles or a material for diffusing the light may beadded.

Meanwhile, cover fixing parts 4931 and 4932 which are inserted into thecover insertion grooves 4916 and 4917 may be formed to protrude fromboth ends of the lamp cover 493 so that the lamp cover 493 is installedand fixed. The cover fixing parts 4931 and 4932 formed at both sides ofthe lamp cover 493 may be coupled or fitted inside the cover insertiongrooves 4916 and 4917 in the form of a hook, and thus the lamp cover 493may be installed and fixed.

The door lighting unit 49 may be selectively turned on/off by a user'soperation. When the door lighting unit 49 is turned on, the rear surfaceof the sub-door 50 and the opening part 403 become bright. When theinside of the refrigerator 1 is brighter than an outside of therefrigerator 1 by turning on the door lighting unit 49, the lightemitted by the door lighting unit 49 is transmitted through the sub-door50. Therefore, the sub-door 50 may be seen to be transparent by theuser, and thus the accommodation space inside the main door 40 may beseen from an outside through the sub-door 50.

Of course, the main lighting unit 85 may be separately provided insidethe refrigerator compartment 12. When the main lighting unit 85 isturned on/off, the space inside the refrigerator 1 may be seen from theoutside through the sub-door 50. The main lighting unit 85 providedinside the refrigerator compartment 12 may be turned on/off togetherwith the door lighting unit 49, or may be independently turned on/off.

Meanwhile, a heater support part 432 which protrudes backward is formedat the rear surface of the frame stepped part 431. The heater supportpart 432 may be formed along a perimeter of the frame stepped part 431,and may be formed to protrude backward. And a protruding position of theheater support part 432 is located at an outside (an upper side in FIG.13) of the frame stepped part 431 so that the frame heater 4321 islocated at an outer end of the frame stepped part 431.

And the frame heater 4321 heats a corner of the frame stepped part 431at which there is a high possibility of dew condensation. The corner ofthe frame stepped part 431 is a portion which is in contact with anouter portion of the sub-door gasket 591, has a relatively lowtemperature, is in contact with external air, and thus has the highpossibility of dew condensation. Therefore, the outside of the framestepped part 431 is heated by the frame heater 4321, and the dewcondensation is prevented.

Meanwhile, door restricting members 4301 and 5721 are provided atpositions corresponding to the main door 40 and the sub-door 50,respectively. The door restricting members 4301 and 5721 enable thesub-door 50 for itself to be restricted to the main door 40 without aseparate restricting structure, and thus prevent the sub-door 50 frombeing undesirably opened by an inertial force generated when the maindoor 40 is rotated.

Specifically, a first magnet installation part 430 is formed at an innerside surface of the door frame 43 which forms an upper surface of theopening part 403, and a first magnet 4301 is installed and fixed to thefirst magnet installation part 430.

And a second magnet installation part 572 is formed at an upper portionof the sub-door 50 corresponding to the first magnet installation part430, and a second magnet 5721 is installed and fixed to the secondmagnet installation part 572. The second magnet installation part 572 isformed at an inner side surface of an upper cap decoration 57 whichforms an upper surface of the sub-door 50, and thus the second magnet5721 is not exposed to the outside.

While the sub-door 50 is closed, the first magnet 4301 and the secondmagnet 5721 are located at positions which face each other, and alsodisposed so that facing surfaces thereof have different polarities fromeach other. Therefore, the sub-door 50 is maintained in a closed stateby an attraction between the first magnet 4301 and the second magnet5721. Of course, when a rotating force of the sub-door 50 applied by auser's operation is larger than a magnetic force of the first magnet4301 and the second magnet 5721, the sub-door 50 may be rotated.

When the first magnet 4301 and the second magnet 5721 are located on thesame extension line, the magnetic force may be applied strongly. Anarrangement structure of the first magnet 4301 and the second magnet5721 is in parallel with an extending direction of a rotating axis ofthe sub-door 50. Therefore, when the sub-door 50 starts to be opened,the first magnet 4301 and the second magnet 5721 cross each other, andthus the magnetic force may be considerably weakened. Accordingly, afterthe sub-door 50 is rotated at a predetermined angle, opening of thesub-door 50 may be smoothly performed.

Meanwhile, the cap decoration 45 is provided at the upper end of themain door 40. Although not illustrated in the drawings, the foamingsolution is injected into an internal space formed by the outer plate41, the door liner 42, the door frame 43 and the cap decoration 45, andthus the insulation is formed therein. An opening device accommodationpart 452 is formed at the cap decoration 45 to be recessed downward. Theopening device accommodation part 452 may be shielded by a capdecoration cover 453.

FIG. 14 is an exploded perspective view of an installation structure ofa door opening device according to the embodiment of the presentinvention. And FIG. 15 is a view illustrating an operation state of thedoor opening device.

As illustrated in the drawings, the opening device accommodation part452 is formed at the cap decoration 45 on an upper surface of the maindoor 40. And a door opening device 70 may be provided inside the openingdevice accommodation part 452. An opened upper surface of the openingdevice accommodation part 452 is shielded by the cap decoration cover453.

The door opening device 70 for automatically opening the main door 40may include a driving motor 72 which is provided inside an openingdevice case 71, a push rod 74 which pushes and opens the main door 40,and gears 73 which transmits power of the driving motor 72 to the pushrod 74.

A rack gear 741 which is engaged with the gears 73 is formed at an outersurface of the push rod 74, and thus may be inserted and withdrawnthrough a rod hole 4511 formed at the rear surface of the main door 40.

And the push rod 74 is formed to have a predetermined curvature.Therefore, even when the main door 40 is rotated, a front end of thepush rod 74 may continuously push the cabinet 10 while being maintainedin a stably contacting state with a front surface of the cabinet 10, andthus may open the main door 40.

In a state in which the user is holding food and thus cannot use his/herhands, the main door 40 may be rotated at a predetermined angle by thedoor opening device 70, and thus the user may put a part of his/her bodylike an elbow therein, and may open the main door 40.

For example, by the operation of the door opening device 70, the maindoor 40 may be opened so that a distance D between the main door 40 andthe adjacent refrigerator compartment door 20 is about 90 mm. At thispoint, a rotating angle of the main door 40 may be 24° to 26°. When therefrigerator compartment door 20 is automatically opened by the distanceD, the user may put the elbow or a part of his/her body in an opened gapof the refrigerator compartment door 20, and may additionally open therefrigerator compartment door 20 even while holding an object and thuscannot use his/her hands.

Of course, since the door opening device 70 is disposed inside the capdecoration 45 having a limited width, a length of the push rod 74 whichis inserted and withdrawn is limited. Therefore, to minimize the lengthof the push rod 74, the door opening device 70 is located at a positionas close as possible to a rotating axis of the main hinge 401 so that aforce for opening the main door 40 may be effectively transmitted. Andto ensure an opening angle of the main door 40, the gears 73 may becombined and arranged so that the push rod 74 having the predeterminedlength is maximally withdrawn.

The door opening device 70 may be installed at the opening deviceaccommodation part 452 by a screw. And the door opening device 70 may besupported at an inside of the opening device accommodation part 452 by ashock absorbing member through which the screw passes, and thusvibration and noise generated when the door opening device 70 isoperated may be prevented.

Meanwhile, the door opening device 70 is selectively driven by theuser's operation, and rotates the main door 40 by an operation of thedriving motor 72 when a door opening signal is input by the user. Atthis point, since the user's hands cannot be used, an operation input ofthe door opening device 70 may be performed in a position detectingmethod or a motion detecting method, instead of a direct input method bythe user's body contact. This will be described again below in detail.

FIG. 16 is a cross-sectional view taken along line 16-16′ of FIG. 1.

As illustrated in the drawing, in the main door 40, an externalappearance formed at both sides of the opening part 403 is formed bycoupling the outer plate 41, the door frame 43 and the door liner 42.

At this point, a front support part 437 which is bent to support theouter plate 41 may be formed at a front end of the door frame 43. Afront accommodation part 4371 in which an end of the outer plate 41 isintroduced in a bent state may be formed at an end of the front supportpart 437.

The end of the outer plate 41 which is located at the frontaccommodation part 4371 forms a multi-bent part 411 which iscontinuously bent several times. The multi-bent part 411 forms one endof the opening part 403. At this point, the one end of the opening part403 at which the multi-bent part 411 is located is close to a handle 561formed at a second side frame 56 of the sub-door 50.

The multi-bent part 411 is bent at a portion forming the front surfaceof the main door 40 to have a predetermined slope, and forms a firstbent part 4111. An inclined surface of the first bent part 4111 may beformed to be directed toward the opening part 403, and an end of thefirst bent part 4111 forms one end of the opening part 403.

And a second bent part 4112 which is bent in a direction opposite to thefirst bent part 4111 is formed at the end of the first bent part 4111.And a third bent part 4113 which is bent in parallel with the frontsurface of the main door 40 is formed at an extending end of the secondbent part 4112. The second bent part 4112 and the third bent part 4113may be located inside the front accommodation part 4371, and may be inclose contact with and supported by the front support part 437.

Therefore, the one end of the opening part 403 at which the multi-bentpart 411 is formed is a portion at which the handle 561 of the sub-door50 is located, and the user's hand comes in and out frequently. In aprocess in which the user's hand comes in and out, the user's hand maybe in contact with one end of the opening part 403. At this point, theuser's hand may smoothly come in and out without being caught orscratched by the inclined surface of the first bent part 4111. At thesame time, strength may be reinforced by the multi-bent part 411, andthe outer plate 41 may be prevented from being deformed by a shockgenerated while the user's hand comes in and out frequently.

The handle 561 forms one side surface of the sub-door 50, and is formedlong vertically, and also formed to have a predetermined space betweenthe one side surface of the sub-door 50 and one end of the opening part403, such that the user puts his/her hand therein and then pulls.

Meanwhile, the frame heater 4321 and the heater support part 432 areformed to protrude from the rear surface of the frame stepped part 431of the door frame 43 and thus to heat the frame stepped part 431,thereby preventing the dew condensation.

FIG. 17 is a perspective view of the sub-door. And FIG. 18 is anexploded perspective view of the sub-door when being seen from a front.And FIG. 19 is an exploded perspective view of the sub-door when beingseen from a rear.

As illustrated in the drawings, the sub-door 50 may be formed in a shapecorresponding to that of the opening part 403. The sub-door 50 mayinclude a panel assembly 54 which is formed by stacking a plurality ofglass layers at regular intervals, side frames 55 and 56 which formsboth side surfaces of the sub-door 50, a sub-door liner 59 which forms aperimeter of the rear surface of the sub-door 50, and the upper capdecoration 57 and a lower cap decoration 58 which forms an upper surfaceand a lower surface of the sub-door 50.

The panel assembly 54 forms an entire front surface of the sub-door 50.The panel assembly 54 may include a front panel 541 which forms anexterior of a front surface thereof, and an insulation panel 542 whichis formed to be spaced apart from a rear surface of the front panel 541.A plurality of insulation panels 542 may be provided, and a spacer bar543 is provided between the front panel 541 and the insulation panel 542and between the plurality of insulation panels 542.

The front panel 541 and the insulation panel 542 may be formed of glassor a see-through material, and thus the inside of the refrigerator 1 maybe selectively seen through. And the front panel 541 and the insulationpanel 542 may have an insulating material or an insulating structure,and may be formed to prevent a leak of cooling air in the refrigerator1. A configuration of the panel assembly 54 will be described below indetail.

The side frames 55 and 56 forms both of left and right side surfaces ofthe sub-door 50. The side frames 55 and 56 may be formed of a metallicmaterial, and serves to connect the panel assembly 54 with the doorliner 42.

The side frames 55 and 56 may include a first side frame 55 forming onesurface at which the sub-hinges 51 and 52 are installed, and a secondside frame 56 at which the handle 561 enabling the user to perform arotating operation is formed.

The first side frame 55 is formed long vertically, and also formed toconnect between the upper hinge 51 and the lower hinge 52. Specifically,hinge insertion parts 551 and 552 in which the upper hinge 51 and thelower hinge 52 are inserted are formed at upper and lower ends of thefirst side frame 55, respectively. The hinge insertion parts 551 and 552are formed at the upper and lower ends of the first side frame 55 to berecessed, and may be formed to have a corresponding shape, such that apart of the upper hinge 51 and the lower hinge 52 is matched therewith.

The first side frame 55 may be formed of a metallic material such asaluminum or a material having high strength, and may enable the upperhinge 51 and the lower hinge 52 to be maintained at accurateinstallation positions, such that the installation positions are notchanged by a weight of the sub-door 50. Therefore, the sub-door 50 maymaintain an initial installation position at the main door 40, and anouter end of the sub-door 50 and the opening part 403 of the main door40 may not interfere with each other when being rotated, and maymaintain a very closely contacting state with each other.

Like the first side frame 55, the second side frame 56 may be formed ofthe metallic material or the material having high strength. The secondside frame 56 may be formed to extend from the upper end of the sub-door50 to the lower end thereof, and may have the handle 561 which isrecessed to allow the user to put his/her hand therein.

The upper cap decoration 57 forms the upper surface of the sub-door 50,and connects upper ends of the first side frame 55 and the second sideframe 56, and is also coupled to an upper end of the panel assembly 54and an upper end of the sub-door liner 59.

And an upper hinge installation part 571 is formed at one end of theupper cap decoration 57. The upper hinge installation part 571 isrecessed so that the upper hinge 51 and the hinge cover 53 are installedtherein, and upper surfaces of the hinge cover 53 and the upper capdecoration 57 form the same plane while the hinge cover 53 is installed.

The lower cap decoration 58 forms the lower surface of the sub-door 50,and connects lower ends of the first side frame 55 and the second sideframe 56, and is also coupled to a lower end of the panel assembly 54and a lower end of the sub-door liner 59.

And a lower hinge installation part 581 is formed at one end of thelower cap decoration 58. The lower hinge installation part 581 isrecessed so that the lower hinge 52 is installed therein. And adetection device accommodation part 582 in which a second detectiondevice 81 and a knock detection device 82 are installed is formed at thelower cap decoration 58. The detection device accommodation part 582 maybe shielded by an accommodation part cover 583.

The second detection device 81 which is installed at the lower capdecoration 58 is a device which checks a user's approach, and the knockdetection device 82 is a device which detects a user's knockingoperation on the sub-door 50. The second detection device 81 and theknock detection device 82 are attached to the rear surface of the frontpanel 541, and may be provided at a lower end of the front panel 541close to the second side frame 56. By the second detection device 81 andthe knock detection device 82, the sub-door 50 may selectively becometransparent, and thus an inside of the sub-door 50 may be seen through.Detailed structures of the second detection device 81 and the knockdetection device 82 will be described below.

The sub-door liner 59 forms a shape of a perimeter of the rear surfaceof the sub-door 50, and may be injection-molded with a plastic material.The sub-door liner 59 is coupled to the first side frame 55, the secondside frame 56, the upper cap decoration 57 and the lower cap decoration58. And the foaming solution is injected into an internal space of aperimeter of the sub-door 50 formed by the sub-door liner 59, and theinsulation (not shown) is filled therein, and thus an insulationstructure of the perimeter of the sub-door 50 is provided.

That is, the insulation structure is formed at a center portion of thesub-door 50 by the insulation panel 542 forming the panel assembly 54,and a perimeter of the panel assembly 54 may have the insulationstructure by the insulation.

The sub-door gasket 591 is provided at a rear surface of the sub-doorliner 59. The sub-door gasket 591 is formed to be in close contact withthe main door 40 when the sub-door 50 is closed. Therefore, the leak ofthe cooling air between the main door 40 and the sub-door 50 may beprevented.

FIG. 20 is a cut-away perspective view taken along line 20-20′ of FIG.17. And FIG. 21 is an exploded perspective view of the panel assemblyaccording to the embodiment of the present invention.

As illustrated in the drawings, an entire exterior of the sub-door 50 isformed by the panel assembly 54, and the first side frame 55 and thesecond side frame 56 are coupled to both ends of the panel assembly 54.And the foaming solution is filled in a space formed by the panelassembly 54, the first side frame 55 and the second side frame 56, andforms the insulation.

The panel assembly 54 may include the front panel 541 which forms theentire front surface of the sub-door 50, at least one or more insulationpanels 542 which arc disposed at a rear of the front panel 541, and thespacer bar 543 which supports between the front panel 541 and theinsulation panel 542 and between the plurality of insulation panels 542.

The front panel 541 may be formed of a glass material which isselectively seen through according to a light transmittance andreflectivity, and thus may be referred to as a half mirror. The frontpanel 541 is formed so that a rear of the sub-door 50 is selectivelyseen through according to ON/OFF of the main lighting unit 85 or thedoor lighting unit 49 in the refrigerator 1.

That is, in a state in which the door lighting unit 49 is turned on,light inside the refrigerator 1 penetrates the front panel 541, and thusthe front panel 541 looks transparent. Therefore, a space inside therefrigerator 1 located at the rear of the sub-door 50 or theaccommodation space formed at the main door 40 may be seen from theoutside while the sub-door 50 is closed.

And in a state in which the door lighting unit 49 is turned off, thelight does not penetrate the front panel 541, but is reflected, and thusthe front panel 541 serves as a mirror surface. In this state, the spaceinside the refrigerator located at the rear of the sub-door 50 or theaccommodation space formed at the main door 40 may not be seen from theoutside.

A bezel 5411 is formed along a perimeter of the rear surface of thefront panel 541. The bezel 5411 may be formed so that the light is nottransmitted therethrough, and thus the side frames 55 and 56, the uppercap decoration 57, the lower cap decoration 58 and the spacer bar 543which are coupled to the front panel 541 are prevented from beingexposed forward through the front panel 541.

And the second detection device 81 and the knock detection device 82 maybe disposed at the bezel 5411 which is formed at the lower end of thefront panel 541, and the knock detection device 82 is disposed so as tobe covered.

Meanwhile, in the bezel 5411 which is formed at the lower end of thefront panel 541, a penetration part 5412 may be formed at a positioncorresponding to the second detection device 81. The penetration part5412 may be formed in a shape corresponding to a front surface of thesecond detection device 81, and the bezel 5411 is not printed thereon.

That is, the bezel 5411 having a predetermined width is printed along aperimeter of the front panel 541, except the penetration part 5412. Thepenetration part 5412 enables the light emitted from the seconddetection device 81 not to interfere with the bezel 5411, but to passthrough the front panel 541 and thus to be transmitted and received.

And the front surface of the second detection device 81 which is incontact with the penetration part 5412 may be formed to have the samecolor as that of the bezel 5411. Therefore, even in a state in which thefront surface of the second detection device 81 is exposed by thepenetration part 5412, an area of the penetration part 5412 may not beeasily exposed, and may have a sense of unity with the front panel 541.

Meanwhile, the first side frame 55 and the second side frame 56 areinstalled at the rear surface of the front panel 541. The first sideframe 55 and the second side frame 56 are adhered to both side ends ofthe rear surface of the front panel 541, respectively, and may beadhered to an inside of an area of the bezel 5411.

And the spacer bar 543 is formed at the perimeter of the rear surface ofthe front panel 541. The spacer bar 543 enables the front panel 541 andthe insulation panel 542 to be spaced apart from each other, and alsoserves to seal therebetween.

The spacer bar 543 may also be disposed between the plurality ofinsulation panels 542. The front panel 541, the insulation panel 542 andthe plurality of spacer bars 543 may be bonded to each other by anadhesive, and a sealant may be coated to seal among the front panel 541,the insulation panel 542 and the spacer bar 543.

The insulation panel 542 may be formed to have a size smaller than thatof the front panel 541, and may be located within an internal area ofthe front panel 541. And the insulation panel 542 may be chemicalstrengthening glass in which glass is soaked in an electrolyte solutionat a glass transition temperature or more, and thus chemicallystrengthened.

A low-radiation coating layer for reducing heat transfer into thestorage compartment due to radiation may be formed at a rear surface ofthe insulation panel 542. Glass on which the low-radiation coating layeris formed is referred to as low-e glass. The low-radiation coating layermay be formed by sputtering silver or the like on a surface of theglass.

A sealed space between the front panel 541 and the insulation panel 542and a sealed space between the plurality of insulation panels 542 whichare formed by the spacer bar 543 may create a vacuum state so as to beinsulated.

If necessary, an inert gas for the insulation, such as argon, may befilled in the sealed space between the front panel 541 and theinsulation panel 542 and the sealed space between the plurality ofinsulation panels 542. The inert gas has more excellent insulationproperty than that of general air. Therefore, insulation performance maybe ensured by forming a predetermined space between the front panel 541and the insulation panel 542 and between the plurality of insulationpanels 542 in which the inert gas is filled.

The insulation panel 542 may be formed in a single panel, and may beinstalled to be spaced apart from the front panel 541. If necessary, twoor more insulation panels 542 may be provided to be spaced apart fromeach other.

Hereinafter, a structure of the front panel 541 having variousapplicable types of half mirror structures will be described.

FIG. 22 is a cross-sectional view schematically illustrating an exampleof a front panel of the panel assembly.

As illustrated in the drawing, the front panel 541 according to anexample embodiment may include a glass layer 5413 which forms anexterior, a vacuum deposition layer 5414 which is formed at a rearsurface of the glass layer 5413, a bezel print layer 5415 which isformed at a rear surface of the vacuum deposition layer 5414, and atransparent print layer 5416 which forms entire rear surfaces of thebezel print layer 5415 and the vacuum deposition layer 5414.

Specifically, the glass layer 5413 may be formed of green glass which iswidely used as transparent glass, and forms an entire surface of thefront panel 541. Of course, various other transparent glass materials,such as white glass, other than the green glass may be used.

The vacuum deposition layer 5414 serves to enable the front panel 541 tohave a half glass property, and may be formed at the rear surface of theglass layer 5413 by vacuum-depositing a titan compound (TiO₂). That is,the vacuum deposition layer 5414 is formed at the entire rear surface ofthe glass layer 5413. While the door lighting unit 49 is not turned on,the light is reflected by the vacuum deposition layer 5414, and thus thefront panel 541 looks like a mirror when being seen from a front.

The bezel print layer 5415 forms the perimeter of the rear surface ofthe front panel 541, and the bezel 5411 may be formed by the bezel printlayer 5415. The bezel print layer 5415 is formed so that the light isnot transmitted therethrough even while the door lighting unit 49 isturned on, and thus elements which are disposed along the perimeter ofthe rear surface of the front panel 541 may be shielded.

And the transparent print layer 5416 may be formed at the entire rearsurface of the front panel 541 including the bezel print layer 5415 andthe vacuum deposition layer 5414. The transparent print layer 5416 maybe formed to be transparent, such that the light is transmittedtherethrough, and serves to protect the front panel 541 while the frontpanel 541 or the panel assembly 54 is processed.

In particular, the transparent print layer 5416 prevents the vacuumdeposition layer 5414 from being damaged. For coupling with theinsulation panel 542, the front panel 541 is formed so that the spacerbar 543 or the like is attached thereto. At this point, the front panel541 may be manufactured separately from the insulation panel 542, andthen transported. In this process, when the transparent print layer 5416is not provided, the vacuum deposition layer 5414 may be damaged, andthus may not perform a half glass function. Therefore, in a structure inwhich the vacuum deposition layer 5414 is formed at the rear surface ofthe glass layer 5413, the transparent print layer 5416 should beprovided.

FIG. 23 is a cross-sectional view schematically illustrating anotherexample of the front panel of the panel assembly.

As illustrated in the drawing, the front panel 541 according to anotherexample embodiment may include a glass layer 5413 which forms anexterior, a ceramic print layer 5417 which is formed at a front surfaceof the glass layer 5413, and a bezel print layer 5415 which is formed ata rear surface of the glass layer 5413.

Specifically, the glass layer 5413 is formed of a glass material throughwhich the light is transmitted, and also which is seen through. A glassmaterial called dark gray glass which imperceptibly has a dark graycolor in a transparent state may be used.

When the door lighting unit 49 is not turned on, and thus the frontpanel 541 is in a mirror-like state, the dark gray color of the glasslayer 5413 serves to subsidiarily provide a color sense which enablesthe front panel 541 to have a texture which looks like an actual mirror.

The ceramic print layer 5417 is formed at the entire front surface ofthe glass layer 5413, and may be formed in a silk screen printing usingreflectance ink which reflects the light.

The reflectance ink includes the titan compound (TiO₂) as a maincomponent, a viscosity-controlling resin, an organic solvent, and anadditive. The reflectance ink may be manufactured to have apredetermined viscosity for the silk screen printing.

And the ceramic print layer 5417 may be formed in a thickness of 40 to400 nm. And the ceramic print layer 5417 may have flatness similar to amirror surface through the silk screen printing using the reflectanceink, and may also be formed like the mirror surface when beingreinforced by heating.

The ceramic print layer 5417 is separately formed on the surface of theglass layer 5413, and has a different refractive index from that of theglass. Therefore, some of the light incident from the outside of therefrigerator 1 to the front panel 541 may be reflected by the ceramicprint layer 5417, and the rest may be reflected by the glass layer 5413,and may have an effect like the mirror due to an interference effect ofthe light which is reflected. That is, due to the interference effect ofthe light which is reflected by a boundary surface of another mediumhaving a different refractive index, the front panel 541 may look likethe mirror when being seen from an outside.

However, when the door lighting unit 49 is turned on, the light isemitted from the inside of the refrigerator 1 toward the glass layer5413, and the light transmitted through the glass layer 5413 passesthrough the ceramic print layer 5417. Therefore, the front panel 541 maylook transparent when being seen from the outside of the refrigerator 1,and the space in the refrigerator 1 may be visible.

At this point, the ceramic print layer 5417 is formed so that thetransmittance of the front panel 541 is about 20% to 30%. When thetransmittance is 20% or less, it is difficult to see through the spacein the refrigerator 1 due to a low transparency of the front panel 541even while the door lighting unit 49 is turned on. And when thetransmittance is 30% or more, the space in the refrigerator 1 is visibleeven while the door lighting unit 49 is turned off, and thus the surfaceeffect like the mirror may not be expected. Therefore, for the halfmirror effect, it is preferable that transmittance of the front panel541 is about 20% to 30%.

And to form a surface having a high brightness, such as the mirrorsurface, the ceramic print layer 5417 is reinforced by heating to apredetermined temperature. An organic component is completely removedthrough the heating, and the titan compound (TiO₂) is calcined on theglass layer 5413.

Meanwhile, when the front panel 541 is heated after the ceramic printlayer 5417 is printed by the silk screen printing, the heating isperformed at a high temperature so that the organic component of thereflectance ink is completely removed, and the titan compound iscalcined. However, when the heating is performed at an excessively hightemperature, bending may occur. Therefore, it is preferable that theheating is performed within a range at which the surface is notdeformed. And for removing of the organic component and calcination ofthe titan compound, the front panel 541 may be heated in stages atdifferent temperatures.

And the bezel print layer 5415 forms the perimeter of the rear surfaceof the front panel 541, and the bezel 5411 may be formed by the bezelprint layer 5415. The bezel print layer 5415 is formed so that the lightis not transmitted therethrough even while the door lighting unit 49 isturned on, and thus may shield the elements which are disposed along theperimeter of the rear surface of the front panel 541.

Meanwhile, the bezel print layer 5415 may be formed in an inorganicprinting method (glass printing). The bezel print layer 5415 may beprinted using a ceramic pigment as a main component in which frit, aninorganic pigment and oil are mixed. Therefore, in the bezel print layer5415, the resin is decomposed and volatilized by the heating in theglass reinforcing process, and the frit melts and covers the pigment,and then may be attached on the surface of the glass layer 5413.

Such an inorganic printing method has smaller fragments and higherdurability than an organic printing method. And a glass component maymelt and may be integrally molded with the glass layer 5413, and thus ina multi-layering process with the additional insulation panel 542, it ispossible to reduce heat loss and also to provide an excellent adhesiveproperty.

FIG. 24 is a cross-sectional view schematically illustrating stillanother example of the front panel of the panel assembly.

As illustrated in the drawing, the front panel 541 according to stillanother example embodiment may include a glass layer 5413 which forms anexterior, a hard coating layer 5418 which is formed at a front surfaceof the glass layer 5413, and a bezel print layer 5415 which is formed ata rear surface of the glass layer 5413.

Specifically, the glass layer 5413 is formed of a glass material throughwhich the light is transmitted, and also which is seen through. A glassmaterial called gray glass which imperceptibly has a dark gray color ina transparent state may be used.

The gray glass has a somewhat brighter color than the dark gray glassdescribed in the above-described example embodiment. This difference maybe caused by a difference between the ceramic print layer 5417 and thehard coating layer 5418 which are formed on the glass layer 5413.

When the door lighting unit 49 is not turned on, and thus the frontpanel 541 is in the mirror-like state, the gray color of the glass layer5413 serves to subsidiarily provide a color sense which enables thefront panel 541 to have a texture which looks like the actual mirror.

The hard coating layer 5418 is formed at the entire front surface of theglass layer 5413, and also formed to have a light transmittance of 25 to50% and a reflectivity of 45 to 65%, and to have a half mirror property,such that the transmittance and the reflectivity may be simultaneouslyincreased.

The hard coating layer 5418 may be formed in a thickness of about 30 to80 nm, and may be configured with triple layers of iron, cobalt andchrome. Of course, one or two layers of the triple layers may beomitted, considering the transmittance, the reflectivity and a colordifference.

The hard coating layer 5418 may be formed in an atmospheric pressurechemical vapor deposition (APCVD) method in which a vaporized coatingsubstance is formed on the entire surface of the glass layer 5413, or ina spraying method in which a liquid coating material is sprayed.

The hard coating layer 5418 is separately formed on the surface of theglass layer 5413, and has a different refractive index from that of theglass layer 5413. Therefore, some of the light incident from the outsideof the refrigerator 1 to the front panel 541 may be reflected by thehard coating layer 5418, and the rest may be reflected by the glasslayer 5413. Therefore, the front panel 541 may have an effect like themirror due to an interference effect of the light which is reflected.That is, due to the interference effect of the light which is reflectedby a boundary surface of another medium having a different refractiveindex, the front panel 541 may look like the minor when being seen froman outside.

However, when the door lighting unit 49 is turned on, the light isemitted from the inside of the refrigerator 1 toward the glass layer5413, and the light transmitted through the glass layer 5413 passesthrough the hard coating layer 5418. Therefore, the front panel 541 maylook transparent when being seen from the outside of the refrigerator 1,and the space in the refrigerator 1 may be visible.

The hard coating layer 5418 is formed so that the transmittance of thefront panel 541 is about 20% to 30%. When the transmittance is 20% orless, it is difficult to see through the space in the refrigerator 1 dueto a low transparency of the front panel 541 even while the doorlighting unit 49 is turned on. And when the transmittance is 30% ormore, the space in the refrigerator 1 is visible even while the doorlighting unit 49 is turned off, and thus the surface effect like themirror may not be expected. Therefore, for the half mirror effect, it ispreferable that transmittance of the front panel 541 is about 20% to30%.

The bezel print layer 5415 forms the perimeter of the rear surface ofthe front panel 541, and the bezel 5411 may be formed by the bezel printlayer 5415. The bezel print layer 5415 is formed so that the light isnot transmitted therethrough even while the door lighting unit 49 isturned on, and thus may shield the elements which are disposed along theperimeter of the rear surface of the front panel 541. The bezel printlayer 5415 may be formed in the inorganic printing method.

FIG. 25 is a cross-sectional view of the sub-door.

As illustrated in the drawing, the side frames 55 and 56 are provided atboth sides of the panel assembly 54. The side frames 55 and 56 may beattached and fixed to the front panel 541, may be coupled to thesub-door liner 59 so as to form a space in which the insulation isaccommodated, and may also insulate the perimeter of the sub-door 50.

The second side frame 56 is formed at a position which faces the firstside frame 55, and may be configured to form another side surface of thesub-door 50. And a first front bent part 553 and a first rear bent part554 may be formed at both ends of the first side frame 55.

The first front bent part 553 may be formed to be bent and thus to be incontact with the rear surface of the front panel 541, and may extend toa position of the spacer bar 543. Therefore, a temperature outside thesub-door 50 may be transferred to the rear surface of the front panel541 along the first side frame 55 formed of the metallic material, andthus the dew condensation at one side of the front panel 541 which is incontact with the first front bent part 553 may be prevented.

And a first heater installation groove 5531 at which a sub-door heater502 is installed may be further formed at the first side frame 55. Thefirst heater installation groove 5531 may be formed at an end of thefirst front bent part 553 so that the sub-door heater 502 is disposed ata position close to the spacer bar 543. Therefore, the sub-door heater502 may be vertically disposed long along the first side frame 55. Dueto a property of the first side frame 55 formed of the metallicmaterial, the dew condensation at the front panel 541 may be preventedby heating the rear surface of the front panel 541 which is in contactwith the first front bent part 553.

The first rear bent part 554 is bent from a rear end of the first sideframe 55, and coupled to the sub-door liner 59. At this point, the firstrear bent part 554 is formed to support the sub-door liner 59, and maybe formed to support a load transmitted through the sub-door gasket 591when the sub-door 50 is closed.

The second side frame 56 is provided at a position which faces the firstside frame 55, and may be configured to form still another side surfaceof the sub-door 50. The second side frame 56 is formed to be located ata position close to one surface of the opening part 403 of the main door40. And a second front bent part 562 and a second rear bent part 563 maybe formed at both ends of the second side frame 56.

The second front bent part 562 extends from an end of the second sideframe 56, and is recessed to form the handle 561 in which the user'shand is put. The handle 561 may be formed to be recessed toward alateral side of the panel assembly 54. Therefore, the handle 561 is notexposed, and only a part of the second side frame 56 may be exposedforward when being seen from a front.

And the second front bent part 562 forms the handle 561, and may beformed to extend from one end of the second side frame 56 and to be incontact with the rear surface of the front panel 541. Therefore, atemperature outside the sub-door 50 may be transferred to the rearsurface of the front panel 541 along the second side frame 56 formed ofthe metallic material, and thus the dew condensation at one side of thefront panel 541 which is in contact with the second front bent part 562may be prevented.

Specifically, the second front bent part 562 is recessed from an outerside further than the front panel 541 toward the front panel 541, and arecessed end may be formed to be recessed inward further than an outerend of the front panel 541. And the second front bent part 562 may belocated at a rear of the front panel 541, and thus the user may puthis/her hand into the handle 561 formed by the second front bent part562, and then may rotate the sub-door 50.

And a second heater installation groove 5621 at which the sub-doorheater 502 is installed may be further formed at the second front bentpart 562. The second heater installation groove 5621 enables thesub-door heater 502 to be disposed at a position close to the spacer bar543. Therefore, the sub-door heater 502 may be vertically disposed longalong the second side frame 56. Due to a property of the second sideframe 56 formed of the metallic material, the dew condensation at thefront panel 541 may be prevented by heating the rear surface of thefront panel 541 which is in contact with the second front bent part 562.

A portion of an inner side surface of the second front bent part 562which is in contact with the front panel 541 may be formed to berounded, and thus may allow the user to easily grip and pull forward theportion.

Meanwhile, the second rear bent part 563 is bent from a rear end of thesecond side frame 56, and coupled to the sub-door liner 59. At thispoint, the second rear bent part 563 is formed to support the sub-doorliner 59, and may be formed to support the load transmitted through thesub-door gasket 591 when the sub-door 50 is closed.

FIG. 26 is an exploded perspective view illustrating a couplingstructure of the sub-door and the upper hinge. And FIG. 27 is a partialperspective view illustrating an installed state of the upper hinge.

As illustrated in the drawings, the upper hinge installation part 571which is recessed so that the upper hinge 51 and the hinge cover 53 areinstalled therein may be formed at the upper cap decoration 57 of thesub-door 50. The upper hinge installation part 571 is formed at an upperend of the upper cap decoration 57, and may be formed to be connected tothe adjacent first side frame 55.

That is, the hinge insertion part 551 formed at an upper end of thefirst side frame 55 and the upper hinge installation part 571 of theupper cap decoration 57 may be connected to each other, and thus theupper hinge 51 may be installed at a corner of the sub-door 50 to whichthe upper hinge installation part 571 and the hinge insertion part 551are connected. And although not illustrated, the lower cap decoration 58provided at the lower end of the sub-door 50 has the same structure, andthus the lower hinge 52 may be installed at a corner of the sub-door 50.

A hinge accommodation part 5711 which is recessed to have a shapecorresponding to the upper hinge 51 is formed at the upper hingeinstallation part 571. And a hinge fixing hole 5712 in which the screwpassed through the upper hinge 51 is fastened is formed at the hingeaccommodation part 5711.

And an electric wire guide part 5714 and an electric wire hole 5713through which an electric wire L disposed at the upper hinge 51 passesmay be formed at one side of the upper hinge installation part 571. Theelectric wire L guided through the electric wire guide part 5714 isconnected to the second detection device 81 and the knock detectiondevice 82, and guided to the upper cap decoration 57 via the lower capdecoration 58 and the second side frame 56. Then, the electric wire Lmay be introduced into the electric wire guide part 5714 through theelectric wire hole 5713 formed at the upper hinge installation part 571,and may be guided to an outside of the sub-door 50 through the electricwire guide part 5714. The electric wire L guided along the electric wireguide part 5714 is guided in an extending direction of the upper hinge51, and introduced into the main door 40 through the hinge hole 433 ofthe main door 40 together with one side of the upper hinge 51.

Meanwhile, the upper hinge 51 is installed and fixed to the upper hingeinstallation part 571 by a screw, and may include a door installationpart 511 which is fixed to the sub-door 50, and a rotary coupling part512 which is rotatably coupled to the main door 40.

And the door installation part 511 may include a horizontal part 5111which is fixed to the upper hinge installation part 571, and a verticalpart 5112 which is fixed to the hinge insertion part 551 of the firstside frame 55. The horizontal part 5111 and the vertical part 5112 areformed perpendicularly to each other, and thus the upper hinge 51 may bemaintained in a fixed state to a corner of the upper end of the sub-door50.

The rotary coupling part 512 may be formed to extend from an end of thehorizontal part 5111 toward the outside of the sub-door 50. The rotarycoupling part 512 may be formed to be bent in one direction, and a hingeshaft 5121 may be formed at an extending end thereof. The hinge shaft5121 is formed to extend downward from the plate-shaped rotary couplingpart 512.

And a cut-away part 5122 is formed at the rotary coupling part 512 tohave the same shape as a shape that the rotary coupling part 512 is bentlaterally. The cut-away part 5122 is formed to be recessed inward fromone side at which the hinge shaft 5121 is formed. And the rotarycoupling part 512 may be cut so as to be rounded in a rotating radiusdirection of the sub-door 50 when the sub-door 50 is opened and closed.Therefore, when the sub-door 50 is rotated to be opened while the upperhinge 51 is coupled to the main door 40, one end of the door frame 43forming the hinge hole 433 is inserted into the cut-away part 5122.

And a flange 5123 which prevents a deformation of the rotary couplingpart 512 and reinforces strength may be formed along an outer end of therotary coupling part 512. The flange 5123 may be formed to extend in adirection which perpendicularly intersects with the rotary coupling part512.

A stopper 5124 may be further formed at one end of the rotary couplingpart 512. The stopper 5124 is formed at one side of the rotary couplingpart 512 close to the hinge shaft 5121, and extends downward so as tointerfere with one side of the main door 40 or the hinge hole 433 whilethe sub-door 40 is rotated to be completely opened, and thus preventsthe sub-door 50 from being further opened.

The hinge cover 53 is formed to shield an opening of the upper hingeinstallation part 571 and also to shield the upper hinge 51 from anupper side thereof. The hinge cover 53 may include a cap decorationshielding part 531 which shields the upper hinge installation part 571,and a hinge shielding part 532 which shields the rotary coupling part512 of the upper hinge 51.

The cap decoration shielding part 531 may have a shape corresponding tothe upper hinge installation part 571, and may also have a plurality ofscrew holes 5311 so that a screw is directly fastened to the upper capdecoration 57, or the screw passing through the door installation part511 is moved in and out.

The hinge shielding part 532 may be formed to extend along a shape ofthe rotary coupling part 512 of the upper hinge 51, and may also beformed to cover the rotary coupling part 512 from an upper side thereof.And the hinge shielding part 532 is disposed to be somewhat spaced apartfrom the rotary coupling part 512, and thus to form a space between thehinge shielding part 532 and the rotary coupling part 512, and thus theelectric wire L passed through the electric wire guide part 5714 may beguided through the space between the hinge shielding part 532 and therotary coupling part 512.

FIG. 28 is a longitudinal cross-sectional view illustrating a couplingstructure of the upper hinge.

As illustrated in the drawing, the upper hinge 51 has a structure whichis installed and fixed to the upper hinge installation part 571 of theupper cap decoration 57, and shielded by the hinge cover 53.

And while the sub-door 50 is installed at the main door 40, the upperhinge 51 is inserted into the hinge hole 433, and the rotary couplingpart 512 of the upper hinge 51 is located inside the main door 40.

In this state, the hinge shaft 5121 of the upper hinge 51 may beinserted into a shaft installation part 438 of the main door 40. Theshaft installation part 438 may be fixed to the inside of the main door40 by a separate member, and may be integrally formed with the doorframe 43 forming the main door 40. The shaft installation part 438 isformed to form a space in which the hinge shaft 5121 is inserted, and tobe rotated while a rotating shaft is inserted into the shaftinstallation part 438.

And when the sub-door 50 is rotated to be opened while the upper hinge51 is coupled to the main door 40, the upper hinge 51 is also rotatedwith rotation of the sub-door 50. At this point, a side end of the hingehole 433 is inserted into the cut-away part 5122 of the upper hinge 51,and thus interference may be prevented.

Due to such a structure of the upper hinge 51, the sub-door 50 may berotatably disposed inside the opening part 403 of the main door 40 whilethe sub-door 50 is closed. And the upper hinge 51 extends laterally, andis rotatably coupled to the inside of the main door 40, and thus theinterference of the upper hinge 51 is prevented while the sub-door 50 isclosed. Therefore, an outer surface of the sub-door 50 and an innersurface of the opening part 403 may be formed to be in close contactwith each other, and thus even when the sub-door 50 is rotated, thesub-door 50 is not sagged or deformed by a stable supporting structureof the upper hinge 51.

And the electric wire L introduced through the electric wire guide part5714 of the upper cap decoration 57 may pass through the hinge hole 433via the hinge shielding part 532 of the hinge cover 53, and may beguided to the inside of the main door 40. Therefore, even while thesub-door 50 is being rotated, the electric wire L is not exposed to theoutside, and is guided to the inside of the main door 40 while beingshielded by the hinge cover 53.

FIG. 29 is a longitudinal cross-sectional view illustrating a couplingstructure of the sub-door and the lower hinge.

As illustrated in the drawing, the lower hinge 52 has the same structureas that of the upper hinge 51, except a bending direction which is bentupward. To install the lower hinge 52, the lower hinge installation part581 is formed at the lower cap decoration 58 to be recessed, and thelower hinge 52 may be installed and fixed to the lower hingeinstallation part 581 and the hinge insertion part 552 of the first sideframe 55. That is, the lower hinge 52 has a structure which is installedand fixed to a corner of the lower end of the sub-door 50.

Meanwhile, each of the upper hinge 51 and the lower hinge 52 has astructure which is inserted and fixed by the first side frame 55. Due toa property of the first side frame 55 formed of the metallic material,the first side frame 55 may stably support the upper hinge 51 and thelower hinge 52, and may stably fix the sub-door 50 without the saggingor the deformation of the sub-door 50 even in an environment in whichthe load is applied. Accordingly, a space between the sub-door 50 andthe main door 40 may be designed and maintained to be very narrow, andthus the external appearance may be enhanced.

The lower hinge 52 and may include a door installation part 521 which isinstalled and fixed to the lower hinge installation part 581 by a screw,and a rotary coupling part 522 which is rotatably coupled to the maindoor 40.

The door installation part 521 may include a horizontal part 5211 whichis fixed to the lower hinge installation part 581, and a vertical part5212 which is fixed to the hinge insertion part 552 of the first sideframe 55. And the rotary coupling part 522 may extend from an end of thehorizontal part 5211 so as to pass through the hinge hole 433 of themain door 40, and a hinge shaft 5221 is formed at one extending end.

The hinge shaft 5221 may be inserted into a shaft installation part 439formed inside the main door 40, and thus the lower hinge 52 may berotatably coupled. And a cutaway part 5222 is formed at the rotarycoupling part 522 so that one side end of the hinge hole 433 is insertedtherein when the sub-door 50 is rotated. And a stopper 5224 whichrestricts rotation of the sub-door 50 may be further formed at therotary coupling part 522.

Like this, the sub-door 50 may be rotatably installed at the main door40 by the upper hinge 51 and the lower hinge 52 which extend laterallyfrom upper and lower ends of one side surface thereof. The sub-door 50which has a relatively heavy weight due to the provided panel assembly54 may be stably fixed to the inside of the opening part 403.

FIG. 30 is an exploded perspective view illustrating a couplingstructure of the knock detection device and the second detection deviceof the sub-door when being seen from a front. And FIG. 31 is an explodedperspective view illustrating a coupling structure of the knockdetection device and the second detection device of the sub-door whenbeing seen from a lower side.

As illustrated in the drawings, the second detection device 81 and theknock detection device 82 may be provided at the lower end of thesub-door 50. The second detection device 81 serves to detect a user'sposition, and to check whether the user stands in front of therefrigerator 1 to operate the refrigerator 1.

The second detection device 81 may be located on an extension line ofthe first detection device 31, and may be arranged vertically with thefirst detection device 31. And an installation height of the seconddetection device 81 corresponds to the lower end of the sub-door 50, andthus an ordinary adult may be detected, but a child having a smallheight, an animal, or other things smaller than the height of the seconddetection device 81 may not be detected.

And the knock detection device 82 is formed to recognize whether theuser knocks on the front panel 541 of the sub-door 50. A certainoperation of the refrigerator 1 may be designated by a knockingoperation detected by the knock detection device 82. For example, thedoor lighting unit 49 may be turned on by the user's knocking operation,and thus the sub-door 50 may become transparent.

A specific structure of the second detection device 81 and the knockdetection device 82 will be described below in detail.

The lower hinge 52 may be installed at the lower cap decoration 58 whichforms the lower surface of the sub-door 50, and the detection deviceaccommodation part 582 may be formed at one side which is distant fromthe lower hinge 52, i.e., one side which is close to the second sideframe 56 so as to be recessed.

The detection device accommodation part 582 is formed to have a sizewhich accommodates the second detection device 81 and the knockdetection device 82. And an opened lower surface of the detection deviceaccommodation part 582 may be shielded by the accommodation part cover583.

The case fixing part 481 to which a screw for fixing the accommodationpart cover 583 to the lower cap decoration 58 is fastened is formed atone side of the accommodation part cover 583. An injection port coverpart 5831 is further formed at the other side of the accommodation partcover 583. The injection port cover part 5831 is formed on the lower capdecoration 58, and also formed to shield a first injection port 5824through which the foaming solution filled to mold an insulation 501 isinjected. And a plurality of hook parts 5832 are formed at an uppersurface of the injection port cover part 5831 to be fitted into thefirst injection port 5824. Therefore, the injection port cover part 5831is fitted into the first injection port 5824, and the case fixing part481 is fixed to the lower cap decoration 58 by fastening the screw, andthe entire accommodation part cover 583 is installed and fixed to thelower cap decoration 58.

When the accommodation part cover 583 is installed at the lower capdecoration 58, the detection device accommodation part 582 may beshielded, and the first injection port 5824 may also be shielded.

And a PCB installation part 5833 is further formed at the accommodationpart cover 583. A detection device PCB 83 for processing a signal of thesecond detection device 81 and the knock detection device 82 isinstalled at the PCB installation part 5833. The detection device PCB 83is connected to the second detection device 81 and/or the knockdetection device 82, and may be seated at the PCB installation part5833.

The detection device PCB 83 serves to process the signal of the seconddetection device 81 and/or the knock detection device 82, and is locatedat a position close to the second detection device 81 and the knockdetection device 82, and configured to process the signals.

In the case in which the detection device PCB 83 for processing thesignal is located at a distance, there may be a problem that noisegenerated when the signal to be processed is transferred through asignal line may be increased. However, since the detection device PCB 83is located at a position at which the second detection device 81 and theknock detection device 82 are installed, a main control part 2 receivesonly a valid knock-on signal. Accordingly, the noise due to the signalline between the main control part 2 and the detection device PCB 83 maybe minimized. That is, the main control part 2 may receive the signal ofwhich the noise is minimized through the detection device PCB 83.Therefore, it is possible to ensure an accurate recognition rate.

In particular, in the case of the knock detection device 82, a signaloutput through a microphone 8211 is indicated by mV unit, but the maincontrol part 2 which controls an entire operation of the refrigerator 1generally receives a signal which is basically indicated by V unit.Therefore, due to a scale difference in a physical signal, it is notpreferable that the main control part 2 determines whether the knock-onsignal is normal.

The refrigerator 1 is an electronic appliance using a high voltage/ahigh current. Therefore, an electrical noise generation amount isrelatively great. This means that the signal of mV unit output from themicrophone 8211 may be further vulnerable to the electrical noise.

Therefore, since the detection device PCB 83 is located close to theknock detection device 82, the noise may be remarkably reduced, and thusthe recognition rate may be enhanced.

Meanwhile, a second injection port 584 through which the foamingsolution is injected is further formed at one side of the lower capdecoration 58 close to the lower hinge 52. The second injection port 584may be shielded by a separate injection port cover 5841. And a pluralityof hook parts 5842 are formed at an upper surface of the injection portcover 5841 to be fitted into the second injection port 584.

A first boss 5821 to which a screw for fixing the second detectiondevice 81 is fastened, and a second boss 5822 for fixing the knockdetection device 82 are respectively formed at a bottom surface of thedetection device accommodation part 582.

And an electric wire hole 5823 is formed at one surface of the detectiondevice accommodation part 582. The electric wire L which is connected tothe detection device PCB 83, the second detection device 81 and theknock detection device 82 may be guided to the outside of the sub-door50 through the electric wire hole 5823.

Meanwhile, a through part 5825 which is opened so that the seconddetection device 81 and the knock detection device 82 are in closecontact with the front panel 541 may be formed at a front surface of thedetection device accommodation part 582 which is in contact with thefront panel 541.

FIG. 32 is an exploded perspective view of the knock detection device.And FIG. 33 is a cross-sectional view taken along line 33-33′ of FIG.17. And FIG. 34 is a cross-sectional view of a microphone module of theknock detection device.

A structure of the knock detection device 82 will be described in detailwith reference to the drawings. The knock detection device 82 mayinclude a microphone module 821 which detects the knock-on signal, aholder 823 which accommodates the microphone module 821, an elasticmember 824 which presses the holder 823 and the microphone module 821toward the front panel 541 so that the holder 823 and the microphonemodule 821 are in close contact with the front panel 541, and a supportmember 825 which supports the elastic member 824 and the holder 823.

The microphone module 821 includes the microphone 8211 which directlysenses a sound wave, and a microphone accommodation part 8212 whichaccommodates the microphone 8211. The microphone 8211 serves to directlysense the sound wave, is formed in a circular shape having apredetermined thickness, and installed and fixed into the microphonemodule 821. One surface of the microphone 8211 may be referred to as asound wave receiving part 8213 which receives the sound wave, and thesound wave receiving part 8213 is disposed toward an opening 8214 of themicrophone accommodation part 8212. And the other side of the microphone8211 may be connected to a signal line 8216, and the signal line 8216may also be connected to the detection device PCB 83.

The microphone accommodation part 8212 is formed of an elastic materialsuch as rubber, and also formed to be in close contact with the frontpanel 541. To this end, the opening 8214 may be formed at one side ofthe microphone accommodation part 8212 close to the microphone 8211installed in the microphone accommodation part 8212, and a circularprotrusion 8215 may be formed at a circumference of the opening 8214.And the protrusion 8215 serves to enable the microphone accommodationpart 8212 not to be inclined in one direction when the microphoneaccommodation part 8212 is in close contact with the front panel 541,and also to enable an entire opened front surface of the opening part403 to be maintained in a closely contacting state with the front panel541.

A predetermined sealed space may be formed between the opening 8214 andthe sound wave receiving part 8213 which are in close contact with eachother by the protrusion 8215. Therefore, a front of the closelycontacting space is sealed by a medium, i.e., the front panel 541.Accordingly, vibration transmitted through an inside of the mediumvibrates air in the predetermined space, and the sound wave due to thevibration may be received by the microphone 8211.

Due to such a sealing process, introduction of external noise orvibration into the predetermined space may be minimized. Thus, an errorin determining a knocking operation or a malfunction due to the externalnoise may be considerably reduced, and a very accurate recognition ratemay be ensured. That is, accuracy in determining the knocking operationwhen a knock-on input is applied may be remarkably increased.

A module seating part 8231 in which the microphone module 821 isaccommodated and which is opened toward the front panel 541 may beformed at the holder 823. The microphone module 821 may be formed sothat at least the protrusion 8215 protrudes further than a front surfaceof the holder 823 while the microphone module 821 is seated on themodule seating part 8231.

A holder slot 8232 through which the signal line connected to themicrophone 8211 passes is formed at the holder 823. The holder slot 8232is formed to be opened at one side of the module seating part 8231.

Also, a first elastic member fixing part 8233 which protrudes so thatthe elastic member 824 is installed and fixed thereto is formed at arear surface of the holder 823. The first elastic member fixing part8233 may be formed to extend and to pass through one end of the elasticmember 824 having a coil shape.

A holder coupling part 8234 which is formed in a hook shape and coupledto the support member 825 is formed at both sides of the holder 823. Dueto the holder coupling part 8234, the holder 823 is coupled so as not tobe separated by the support member 825. And also, due to the hook shapeof the holder coupling part 8234, movement of the holder 823 in adirection which is inserted into the support member 825 is notrestricted.

A front surface of the support member 825 is formed to be opened, andalso formed so that the holder 823 is inserted through the opened frontsurface thereof. And a second elastic member fixing part 8251 whichprotrudes so that the elastic member 824 is installed and fixed theretomay be formed at an inside of the holder 823. The second elastic memberfixing part 8251 may be located on an extension line of the firstelastic member fixing part 8233, and may be inserted so as to passthrough one end of the elastic member 824.

Therefore, even though the elastic member 824 is compressed to press theholder 823, the elastic member 824 may stably press the holder 823toward the front panel 541 without being buckled.

By the elastic member 824, the microphone module 821 may be maintainedin a closely contacting state with the front panel 541, andparticularly, may be always maintained in the closely contacting statewith the front panel 541 without a position change of the microphonemodule 821 due to a shock generated when the main door 40 and thesub-door 50 are closed and opened or an inertial force generated whenthe main door 40 and the sub-door 50 arc rotated.

A support member slot 8252 may be formed at one side of the supportmember 825. The support member slot 8252 may be formed on an extensionline of the holder slot 8232. Therefore, the signal line passing throughthe holder slot 8232 may pass through the support member slot 8252, andmay be connected to the detection device PCB 83.

A support member fixing part 8253 is formed at the other side of thesupport member 825. The support member fixing part 8253 extends outward,and is seated in the second boss 5822 which protrudes from the detectiondevice accommodation part 582. And the screw passes through a screw hole8254 of the support member fixing part 8253, and is fastened to thesecond boss 5822, and the support member 825 is installed and fixed onthe lower cap decoration 58.

Meanwhile, the knock detection device 82 is installed at the area of thebezel 5411 of the front panel 541, and thus the knock detection device82 is not exposed to the outside when being seen from an outside of thefront panel 541.

Meanwhile, the knock detection device 82 is located at an edge of thefront panel 541, but an effective input part for the user's knockingoperation is not limited thereto. In a state in which the knockdetection device 82 is in close contact with the medium, even though theknocking operation is applied to any positions, the sound wave may betransmitted through the continuous same medium due to a property of themicrophone 8211 which detects the sound wave generated by the vibration,instead of the vibration itself, and thus may be effectively detected.Therefore, a position of the knock detection device 82 may be disposedat one end at which the electric wires may be arranged and a visiblearea of the sub-door 50 may also be maximized. At the same time, eventhough the user knocks on any point of the front panel 541, the soundwave may be detected through the microphone 8211 which is in closecontact with the same medium.

Specifically, an area to which a user's knocking input is applied may bean entire area which is defined by the front surface of the front panel541. Most of the front panel 541 except a boundary portion thereof issubstantially a see-through area which selectively becomes transparent,and the knock detection device 82 may not be disposed thereat.

Therefore, it is preferable that the knock detection device 82 islocated at the area of the bezel 5411 in the front panel 541. Inparticular, the bezel 5411 located at an upper end and left and rightsides of the front panel 541 may be minimized by locating the knockdetection device 82 at the lower end of the front panel 541 rather thanboth of the left and right sides thereof. By such a shape of the bezel5411, the see-through area may be expanded. Since the knock detectiondevice 82 is located at the lower end of the front panel 541 on which auser's eyes are relatively less focused, the wider see-through area maybe provided to the user.

Since the knock detection device 82 is located at the area of the bezel5411, is not exposed to an outside, and has a structure which is inclose contact with the front panel 541, the user's knocking operationmay be detected even though the user knocks on any position of the frontpanel 541.

Meanwhile, there may be a lot of environmental factors other than theknocking operation in which the vibrations are exerted on the frontsurface of the front panel 541. The front surface of the panel assembly54 may be vibrated by the shock generated when the main door 40 and thesub-door 50 are opened and closed, an external loud noise or the like,and such an input due to the external environments may be recognized asa knock signal.

Therefore, the detection device PCB 83 may be set so that a user'soperation which knocks several times the front surface of the sub-door50 may be recognized as a normal knock input. More specifically, theuser's operation which knocks several times the front surface of thesub-door 50 at predetermined time intervals may be recognized as thenormal knock input.

For example, when the user knocks twice the front surface of thesub-door 50 within a predetermined time, it may be recognized as thenormal knock input. When a general user's knock pattern is analyzed, itmay be understood that a time interval between a first knock and asecond knock is less than about 600 ms. That is, when it is consideredthat 1 second (s) is 100 ms, a case in which the first knock and thesecond knock are performed at a time interval less than 1 second may berecognized as the normal knock input.

Therefore, by setting the time interval, an abnormal input may beremarkably prevented from being misrecognized as the knock signal.

Meanwhile, there may be a deviation in a knock intensity according tothe user. However, since the medium is the same, it may be understoodthat the deviation in the knock intensity may be large, but a deviationin a vibration pattern is very small. Therefore, the deviation in theknock intensity may be offset through an algorithm, and the normal knockinput may be effectively recognized using a knock input pattern and thetime interval between the knocks as factors.

On the contrary to this, it means that the abnormal input may beremarkably prevented from being recognized as the knock input.

FIG. 35 is an exploded perspective view illustrating a couplingstructure of the second detection device. And FIG. 36 is a partialperspective view illustrating an installed state of the second detectiondevice.

As illustrated in the drawings, the second detection device 81 may belocated inside the detection device accommodation part 582, and may belocated at a lateral side of the knock detection device 82.

The second detection device 81 is a device which detects a user'sapproach, and a position sensing device (PSD) may be used as the seconddetection device 81. That is, the second detection device 81 includes alight emitting part 811 and a light receiving part 812, and is formed sothat the infrared light is emitted from the light emitting part 811, anangle of the reflected light is measured by the light receiving part812, and thus a position of the user is recognized. An approach distancewhich is detected by the PSD may be set, and a detectable distance ofthe second detection device 81 is set to less than 1 m, and thus, whenthe user is located within a distance of 1 m from the front surface ofthe refrigerator 1, it may be recognized that the user is located infront of the refrigerator 1 to operate the refrigerator 1.

Like the knock detection device 82, an installation position of thesecond detection device 81 corresponds to the lower end of the sub-door50 located at an upper side. Since the installation position correspondsto a height of about 1 m from a floor, the child having the small heightor other things having the low height may not be detected.

A pressing member 813 may be further provided at a rear of the seconddetection device 81. The pressing member 813 is formed to press thesecond detection device 81 so that the second detection device 81 isinstalled and fixed to the detection device accommodation part 582, andalso the second detection device 81 is in close contact with the frontpanel 541.

Specifically, a detection device fixing part 8131 which is fixed to arear surface of the second detection device 81 is formed at the pressingmember 813. The detection device fixing part 8131 is coupled to bothside ends of the second detection device 81, and thus the pressingmember 813 and the second detection device 81 may be integrally coupledto each other.

And an elastic part 8132 which protrudes backward to be rounded isformed between the detection device fixing parts 8131. The elastic part8132 may be elastically deformed by a pressure, and an end of theelastic part 8132 which protrudes while the second detection device 81is installed is in close contact with a wall surface of the detectiondevice accommodation part 582, and elastically deformed. Therefore, thesecond detection device 81 may be in close contact with the front panel541 by an elastic restoring force of the elastic part 8132. Therefore,the light emitting part 811 and the light receiving part 812 may becompletely in close contact with the rear surface of the front panel541.

At this point, the front surface of the second detection device 81passes through the through part 5825 formed at the front surface of thedetection device accommodation part 582, and may be disposed at an areaof the penetration part 5412 which is formed at the bezel 5411 to betransparent.

Therefore, the second detection device 81 has a structure which isactually exposed to the outside through the penetration part 5412.However, the second detection device 81 may have a black color or a darkgray color which is the same as or similar to a color of the front panel541 having a half mirror structure, and thus may not be easily seen whenbeing seen from an outside.

That is, the light emitted from the second detection device 81 does notinterfere with the bezel 5411, and the second detection device 81 isprevented from being remarkably exposed, and thus the externalappearance is also prevented from being degraded.

Meanwhile, a pressing member fixing part 8133 is formed at one side ofthe pressing member 813. The pressing member fixing part 8133 is formedto extend outward, and seated at the first boss 5821 which protrudesfrom the detection device accommodation part 582. And the screw passingthrough a screw hole 8134 of the pressing member fixing part 8133 isfastened to the first boss 5821, and thus the pressing member 813 isinstalled and fixed on the lower cap decoration 58.

FIG. 37 is a view illustrating an electric wire arrangement inside thesub-door.

As illustrated in the drawing, in the sub-door 50, while the seconddetection device 81 and the knock detection device 82 are assembled, thedetection device accommodation part 582 is shielded by the accommodationpart cover 583. At this point, the detection device PCB 83 is installedat an inner surface of the accommodation part cover 583, and theelectric wire L which is connected to the second detection device 81,the knock detection device 82 and the detection device accommodationpart 582 is guided to an outside of the detection device accommodationpart 582 through the electric wire hole 5823.

In the sub-door 50, a space in which the insulation 501 is formed isprovided at an outer perimeter of the panel assembly 54, i.e., aninternal area of the upper cap decoration 57, the lower cap decoration58, the first side frame 55 and the second side frame 56.

Therefore, an empty space is formed before the foaming solution formolding the insulation 501 is injected, and the electric wire L passingthrough the electric wire hole 5823 of the detection deviceaccommodation part 582 may be guided along a space formed by the secondside frame 56 and the upper cap decoration 57.

And the electric wire L guided to the upper hinge installation part 571through the electric wire hole 5713 of the upper hinge installation part571 may be covered by the hinge cover 53. And the electric wire L isguided to the inside of the main door 40 through a space between thehinge cover 53 and the upper hinge 51, and is not exposed to the outsideeven while the sub-door 50 is being rotated.

Meanwhile, the first injection port 5824 and the second injection port584 are formed at the lower cap decoration 58, and may be shielded bythe injection port cover 5841 and the injection port cover part 5831formed at the accommodation part cover 583.

The first injection port 5824 is located at a lateral side of thedetection device accommodation part 582, and may be located at aposition close to the second side frame 56. The first injection port5824 is formed as outward as possible. When the first injection port5824 is formed at a position which is at least partially overlapped witha space between the panel assembly 54 and the second side frame 56, itis easy to inject the foaming solution between the panel assembly 54 andthe second side frame 56. However, since the inference may occur due toa shape of the handle 561 formed at the second side frame 56, it ispreferable that first injection port 5824 is formed as outward aspossible.

A foaming solution guide part 585 which is formed inside the firstinjection port 5824 to be rounded toward the second side frame 56 may beformed inside the lower cap decoration 58. Therefore, when the foamingsolution is injected through the first injection port 5824, the foamingsolution may naturally flow to the space between the second side frame56 and the panel assembly 54.

The second injection port 584 is formed on the lower cap decoration 58close to the lower hinge installation part 581. The second injectionport 584 is located to avoid the interference with the lower hingeinstallation part 581. At this point, the second injection port 584 maybe formed at a position which is spaced laterally further than a spaceformed by the first side frame 55 and the panel assembly 54.

A width of the space between the first side frame 55 and the panelassembly 54 is narrow, and thus the foaming solution may overflow whenthe foaming solution is directly injected. To solve the problem, thefoaming solution is primarily injected into a relatively wide spaceformed by the lower cap decoration 58 and the panel assembly 54, andthen naturally flows to the space formed by the first side frame 55 andthe panel assembly 54.

Like this, there is a difference in fluidity of the foaming solutionaccording to positions of the first injection port 5824 and the secondinjection port 584. The foaming solution may be simultaneously injectedat both of the first injection port 5824 and the second injection port584, and may be filled at the perimeter of the sub-door 50.

FIG. 38 is a perspective view illustrating a state in which the foamingsolution is injected into the sub-door. And FIG. 39 is a viewillustrating an arrangement of a vent hole of the sub-door.

Referring to the drawings, in a state in which the accommodation partcover 583 and the injection port cover 5841 are opened, the foamingsolution is injected toward the first injection port 5824 and the secondinjection port 584. At this point, a pressure of the foaming solutioninjected to each of the first injection port 5824 and the secondinjection port 584 may be set differently. That is, the foaming solutionwhich is injected to the first injection port 5824 having a relativelywide flowing space may be injected at a relatively high pressure.

A flowing path of the foaming solution will be described with referenceto FIG. 38. The foaming solution injected to the first injection port5824 is introduced into a space formed by the second side frame 56 andthe panel assembly 54 through the foaming solution guide part 585. Then,the foaming solution flows continuously to a space formed by the uppercap decoration 57 and the panel assembly 54.

The foaming solution injected to the second injection port 584 is firstinjected into the space formed by the lower cap decoration 58 and thepanel assembly 54, and then flows continuously to the space between thefirst side frame 55 and the panel assembly 54.

The foaming solution which is simultaneously injected to both of thefirst injection port 5824 and the second injection port 584 is combinedat an area A of the upper cap decoration 57 or an area B of the firstside frame 55. Then, the foaming solution is fully filled in a spaceformed by the upper cap decoration 57, the first side frame 55 and thesecond side frame 56, and then finally filled in the space formed by thelower cap decoration 58 and the panel assembly 54. After the filling ofthe foaming solution is completed, the first injection port 5824 and thesecond injection port 584 are shielded by the accommodation part cover583 and the injection port cover 5841.

Meanwhile, a vent hole 5921 through which air remaining in the sub-door50 is discharged when the foaming solution is injected is formed at thesub-door liner 59. The vent hole 5921 may be formed at a gasketinstallation groove 592 at which the sub-door gasket 591 formed alongthe sub-door liner 59 is installed.

The gasket installation groove 592 may be formed to be recessed along aperimeter of the sub-door liner 59, and the vent hole 5921 may be formedin the gasket installation groove 592 at regular intervals. And afterthe foaming solution is fully filled, the sub-door gasket 591 isinstalled at the gasket installation groove 592. Therefore, the venthole 5921 may be covered by the sub-door gasket 591, and may not beexposed to an outside.

Meanwhile, the vent hole 5921 may be formed at a partial section of theentire gasket installation groove 592. The vent hole 5921 may be formedat regular intervals along areas A and B at which the upper capdecoration 57 and the first side frame 55 are disposed, andparticularly, may be formed at regular intervals based on a corner atwhich the upper cap decoration 57 and the first side frame 55 meet.

Therefore, the air in the sub-door 50 may be discharged at an area closeto a point at which the foaming solutions injected into the firstinjection port 5824 and the second injection port 584 arc combined. Theair may be continuously discharged until the foaming solution iscompletely filled.

FIG. 40 is a perspective view illustrating an operation state of aprojector of the refrigerator. And FIG. 41 is a cut-away perspectiveview illustrating an internal structure of a freezer compartment of therefrigerator.

As illustrated in the drawings, the freezer compartment 13 may be openedand closed by one pair of the freezer compartment doors 30. And thefirst detection device 31 and a projector 32 may be provided at a rightone (in FIG. 40) of the pair of freezer compartment doors 30.

It is preferable that the first detection device 31 and the projector 32are provided at the right one of the pair of freezer compartment doors30 at which the sub-door 50 is located. And the first detection device31 may be vertically disposed on an extension line of the seconddetection device 81.

An inclined surface 331 which is formed to be inclined downward towardan inside may be formed at a lower portion of the freezer compartmentdoor 30. And the first detection device 31 and the projector 32 may beprovided at the inclined surface 331.

The projector 32 serves to project light on a floor surface located infront of the refrigerator 1. An image P such as a design and a charactermay be projected through the projector 32. For example, when theprojector 32 is turned on, the image P including a word like “Door open”may be displayed on the floor surface located in front of therefrigerator 1.

Meanwhile, the first detection device 31 may be disposed at a lower sideof the projector 32. The projector 32 and the first detection device 31may be formed in one module, and may be installed together at theinclined surface 331.

The first detection device 31 may be configured with a kind of proximitysensor which detects a position, and may be provided at the lower sideof the projector 32, and may detect whether an object is located at aposition of the image P projected by the projector 32.

That is, when the user locates his/her body like a foot on the image Pprojected by the projector 32, the first detection device 31 may detectthe body. A PSD sensor or an ultrasonic sensor may be used as the firstdetection device 31, and various kinds of proximity sensors whichrecognize a distance of about 10 to 20 cm may be used.

The projector 32 and the first detection device 31 may be installed onthe inclined surface 331 to project the image right in front of therefrigerator 1 or at a lower side of the inclined surface 331 and todetect the object. Therefore, an erroneous detection is prevented fromoccurring due to a person or an animal which just passes by therefrigerator 1, an object which performs a cleaning operation or thelike. That is, the user stands at a position close to the refrigerator 1to be detected by the first detection device 31. At this point, when theuser's foot is located right in front of the inclined surface 331 or atthe lower side of the inclined surface 331, the foot is detected by thefirst detection device 31.

Detecting of the first detection device 31 may include a motion ofcovering at least a part of the image P projected by the projector 32for a preset time, a motion of passing through an arca of the image P,and another motion which may be recognized by the first detection device31.

In addition, it may be set that positioning of the user is recognized asan user's operation for operating the refrigerator 1 only when thepositioning is simultaneously detected by a combination of the firstdetection device 31 and the second detection device 81, and thusmalfunction may be minimized. To this end, when the user is detected bythe second detection device 81, the projector 32 may be operated, and adetection value of the first detection device 31 may be valid.

Like this, when both of the first detection device 31 and the seconddetection device 81 validly perform an detection operation, the dooropening device 70 may be operated to open the main door 40. Theembodiment of the present invention has described an example in whichthe main door 40 is opened by the door opening device 70. However, thesub-door 50 or the freezer compartment door 30 may be opened accordingto a position of the door opening device 70.

Meanwhile, the user may grip a freezer compartment handle, and then mayrotate the freezer compartment door 30, and thus the freezer compartment13 may be opened and closed by rotation of the freezer compartment door30. An opening and closing detection device 302 may be provided at afreezer compartment door hinge 301 which rotatably supports the freezercompartment door 30, and whether or not the freezer compartment door 30is opened may be determined by the opening and closing detection device302.

And when the freezer compartment door 30 is opened at a preset angle ormore, and the freezer compartment accommodation member 131 providedinside the freezer compartment door 30 is in a state which may bewithdrawn, the freezer compartment accommodation member 131 may beautomatically withdrawn forward by driving of an accommodation memberwithdrawing device 34.

To this end, the freezer compartment accommodation member 131 having adrawer or basket shape may be supported by a sliding rail 1311 so as tobe inserted into or withdrawn from the freezer compartment 13. And theaccommodation member withdrawing device 34 provided inside the freezercompartment 13 may be formed so that an inserting and withdrawing rod341 is inserted and withdrawn by driving of a motor and a gear assembly.

The inserting and withdrawing rod 341 may be connected to the freezercompartment accommodation member 131, and thus the freezer compartmentaccommodation member 131 may be automatically withdrawn by driving ofthe accommodation member withdrawing device 34. At this time, even whena plurality of freezer compartment accommodation members 131 areprovided, the inserting and withdrawing rod 341 may be connected to allof the plurality of freezer compartment accommodation members 131through a connection member 342, and thus the plurality of freezercompartment accommodation members 131 may be inserted and withdrawn atthe same time.

When the freezer compartment door 30 is rotated to be closed, and thenit is determined that the freezer compartment door 30 is rotated at apredetermined angle or more before being in contact with the freezercompartment accommodation member 131, the accommodation memberwithdrawing device 34 is reversely rotated, and the inserting andwithdrawing rod 341 is inserted, and thus the freezer compartmentaccommodation member 131 may be slid and inserted to an initialposition.

Hereinafter, an operation of the sub-door of the refrigerator accordingto the embodiment of the present invention having the above-describedstructure will be described.

FIG. 42 is a block diagram illustrating a flow of a control signal ofthe refrigerator. And FIG. 43 is a flowchart sequentially illustratingan operation of the sub-door of the refrigerator.

As illustrated in the drawings, the refrigerator 1 includes the maincontrol part 2 which controls the operation of the refrigerator 1, andthe main control part 2 may be connected to a door switch 21. The doorswitch 21 may be provided at the cabinet 10, and may detect opening ofthe refrigerator compartment door 20 or the main door 40, and may alsobe provided at the main door 40, and may detect opening of the sub-door50.

And the main control part 2 may be connected to the main lighting unit85 provided inside the cabinet 10, and may illuminate the inside of therefrigerator 1 when the refrigerator compartment door 20 or the maindoor 40 is opened. And the main control part 2 may be connected to thedoor lighting unit 49, and may enable the door lighting unit 49 to beturned on when the sub-door 50 is opened or the knock-on signal isinput.

And the main control part 2 may be connected to the display unit 60, andmay control an operation of the display unit 60, and may receive anoperating signal through the display unit 60. Also, the main controlpart 2 may be connected to the door opening device 70 and theaccommodation member withdrawing device 34, and may control operationsof the door opening device 70 and the accommodation member withdrawingdevice 34.

The main control part 2 may be connected to a communication module 84.The communication module 84 serves to transmit and receive data such asstate information of the refrigerator 1, program updating, andtransmitting of a using pattern, and may be configured with a devicewhich allows short range communication such as NFC, WiFi and Bluetooth.And setting of the communication module 84 may be performed at thedisplay unit 60.

The main control part 2 may be directly or indirectly connected to thefirst detection device 31, the second detection device 81, the knockdetection device 82 and the projector 32, and may receive the operatingsignals thereof or may control the operations thereof. And when thedetection device PCB 83 is connected to the knock detection device 82and/or the first detection device 31, the detection device PCB 83 may beconnected to the main control part 2. And the knock detection device 82and the detection device PCB 83 may be integrally formed with eachother.

In a general state in which a separate operation is not applied to therefrigerator 1 having the above-described configuration, the sub-door 50is in the opaque state like the minor surface, as illustrated in FIG. 4.In this state, it is impossible to see through the inside of therefrigerator 1.

And in this state, the first detection device 31, the second detectiondevice 81 and the knock detection device 82 are maintained in anactivated state in which the user may input the operation anytime[S110].

In this state, when the user locates in front of the front surface ofthe refrigerator 1 to open the main door 40 or the sub-door 50 of therefrigerator 1, the second detection device 81 detects the user'sposition. At this time, when the user is not an ordinary adult, but achild, the user may not be detected due to a property of the position ofthe second detection device 81. When a height of an object which isbeing cleaning or traveling is lower than that of the second detectiondevice 81, the object may not be detected, and thus the malfunction maybe prevented. Meanwhile, the detecting of the second detection device 81is not essential, and thus may be selectively set by the user'soperation [S120].

Then, when the user performs a knocking operation which knocks on thefront surface of the sub-door 50, i.e., the front panel 541, the knockdetection device 82 may detect the knocking operation, and the detectiondevice PCB 83 determines whether the knocking operation is valid.

Specifically, when the user knocks on the front panel 541, the soundwave due to the vibration generated at this point is transmitted alongthe front panel 541 formed of the same medium, and the microphone 8211which is in close contact with the front panel 541 receives the soundwave.

The received sound wave is filtered and amplified while passing througha filter and an amplifier, and transmitted to the detection device PCB83. The detection device PCB 83 determines the knock with the signalwhich is collected and analyzed to detect the knock signal.

That is, in the case of the sound wave which is generated by a noise ora shock inside or outside the refrigerator 1, there is a difference fromthe sound wave generated by the knocking operation in a propertythereof, and thus the detection device PCB 83 determines whether theuser performs the knocking operation through the signal corresponding tothe property of the knock signal.

Of course, in a certain situation, a signal similar to the knock signalmay be generated, or a shock similar to the knock may be applied to thefront panel 541 due to the user's carelessness or inexperiencedoperation, or the external noise may be recognized as a signal similarto a wavelength of the knock signal.

To prevent misrecognition in the certain situation, the detection devicePCB 83 confirms whether the knock signal is continuously generated in apreset pattern, and also determines whether the pattern is formed withina preset time.

For example, it may be set that, when a signal which is recognized asthe knock is generated twice within one second, the signal may bedetected as the valid knock-on signal. In an analysis of the generaluser's knock pattern, when the knock is performed continuously twice,the time interval is less than one second. Therefore, when a signalrecognition condition is set as described above, the misrecognition inthe certain situation may be prevented, and also the user's knockingoperation may be accurately recognized. Of course, the number of theknock signal and the set time necessary to be recognized as the validknock-on signal may be changed variously.

When a detecting signal is not detected by the second detection device81, or it is determined through the knock detection device 82 that thevalid knock-on signal is not generated, the main control part 2 does notperform a separate control operation, and is maintained in a standbystate.

And while the main door 40 or the sub-door 50 is opened, the seconddetection device 81 and the knock detection device 82 may beinactivated, or may ignore the input signal, and thus the malfunctionmay be prevented [S130].

Meanwhile, when the valid knock-on signal is detected, and the detectiondevice PCB 83 transmits the valid signal to the main control part 2, themain control part 2 turns on the main lighting unit 85 or the doorlighting unit 49.

When the main lighting unit 85 or the door lighting unit 49 is turnedon, the inside of the refrigerator 1 becomes bright, and the lightinside the refrigerator 1 passes through the panel assembly 54. Inparticular, when the light passes through the front panel 541, the frontpanel 541 becomes transparent, and thus the inside thereof may be seenthrough, as illustrated in FIG. 5.

When the sub-door 50 becomes transparent, the user may confirm theaccommodation space inside the main door 40 or the space inside therefrigerator 1, and thus may open the sub-door 50 to store the food, ormay perform a necessary operation.

At this time, the display unit 60 may also be turned on, and may displayoperation information of the refrigerator 1. Therefore, the user maycheck the information output from the display 61 disposed inside themain door 40 through the sub-door 50 [S140].

The turned-on main lighting unit 85 or the door lighting unit 49 may bemaintained in a turned-on state for a preset time, e.g., 10 seconds, andthus may allow the user to sufficiently confirm an internal state of therefrigerator 1. Of course, the display unit 60 may also be maintained ina turned-on state for a preset time.

And it is determined whether the preset time passed while the mainlighting unit 85 or the door lighting unit 49 is turned on. When thepresent time passes, the main lighting unit 85 or the door lighting unit49 is turned off [S150].

And while the main lighting unit 85 or the door lighting unit 49 isturned on, a valid knocking operation signal may be input by the userbefore the preset time passes.

That is, when the user performs the knocking operation to confirm theinside of the refrigerator 1, but a separate operation is not needed,the main lighting unit 85 or the door lighting unit 49 may be turned offbefore the preset time passes.

For example, in a state in which the user confirms an accommodationstate inside the refrigerator 1 within 5 seconds after the main lightingunit 85 or the door lighting unit 49 is turned on, or confirms theinformation displayed on the display unit 60, when it is intended thatthe sub-door 50 becomes opaque, the knocking operation may be performedagain on the front surface of the sub-door 50, i.e., the front panel541.

At this point, when it is determined that the knocking operation isvalid, the main lighting unit 85 or the door lighting unit 49 may beturned off before the preset time passes, and the display unit 60 mayalso terminate an output of the information. Of course, validitydetermination of the knocking operation may be set to be the same as theoperation S130, and if necessary, may be set to another knock inputpattern [S160].

When the preset time passes after the main lighting unit 85 or the doorlighting unit 49 is turned on, or the valid knock-on signal is input,the main lighting unit 85 or the door lighting unit 49 may be turnedoff.

When the main lighting unit 85 or the door lighting unit 49 is turnedoff, the inside of the refrigerator 1 becomes dark, and the outsidethereof is in a bright state. In this state, the light outside therefrigerator 1 is reflected by the front panel 541, and thus the frontsurface of the sub-door 50 is in the mirror-like state, and the user maynot see through the inside thereof. Therefore, the sub-door 50 ismaintained in the opaque state until a new operation is input [S170].

Hereinafter, an operation of the display unit 60 will be described withreference to the drawings.

FIG. 44 is a perspective view illustrating an installed state of thedisplay unit. And FIG. 45 is a view illustrating a configuration of afront surface of the display unit.

As illustrated in the drawings, the display unit 60 is provided at alower end of the opening part 403 of the main door 40. And when the mainlighting unit 85 or the door lighting unit 49 is turned on so that thesub-door 50 becomes transparent, the display unit 60 may also be turnedon together, and thus the user may confirm the information of thedisplay unit 60 through the sub-door 50 even while the sub-door 50 isclosed.

The display unit 60 may be turned on while the sub-door 50 is opened.The user may open the sub-door 50 to operate the display unit 60, andwhen the opening of the sub-door 50 is detected by the door switch 21,the display unit 60 may be activated.

The display 61 is provided at a center of a front surface of the displayunit 60, and the plurality of operating buttons 62 may be provided atboth of left and right sides of the display 61.

The display 61 is a screen through which the operation information ofthe refrigerator 1 is output, and may be selectively turned on and offaccording to the knocking operation on the front panel 541 or theopening and closing of the sub-door 50.

And the operating buttons 62 serve to set the operation of therefrigerator 1, and may include a communication button 621, a lockbutton 622, an auto-door button 623, an auto-drawer button 624, arefrigerator compartment temperature fixing button 625, a freezercompartment temperature fixing button 626, an air cleaning button 627,and a quick freezing button 628. A combination of the operating buttons62 is just an example for convenience of explanation, and is not limitedthereto.

FIG. 46 is a view illustrating a change in a display state of thedisplay unit according to a knocking operation.

As illustrated in the drawing, the display 61 is maintained in an OFFstate until the knocking operation on the front panel 541 is performed.And when the user knocks on the front panel 541, the display 61 isturned on. At this point, a first screen 611 or a second screen 612which outputs a temperature in the refrigerator 1 and a presentoperating function may be output on the display 61.

At this point, since the main lighting unit 85 or the door lighting unit49 is turned on, and the sub-door 50 becomes transparent, theinformation of the display 61 may be indicated even while the sub-door50 is closed.

When the preset time passes after the display unit 60 is turned on, orthe user knocks again on the front panel 541, the display 61 is turnedoff. At this time, the main lighting unit 85 or the door lighting unit49 is also turned off, and the sub-door 50 is in the opaque state, andthus the display 61 is not visible from the outside.

FIG. 47 is a view illustrating the change in the display state when thesub-door is opened and closed.

As illustrated in the drawing, while the sub-door 50 is closed, thedisplay 61 is turned off. And when the sub-door 50 is opened, theopening of the sub-door 50 is detected by the door switch 21, and themain control part 2 turns on the display 61.

When the display 61 is turned on, the operation information of therefrigerator 1 is displayed on the first screen 611, and the firstscreen 611 is changed into the second screen 612 after the preset timepasses, and another operation information of the refrigerator 1 isdisplayed on the second screen 612. At this point, the informationdisplayed on the first screen 611 and the second screen 612 may be setby the user's operation.

For example, the first screen 611 may display all of the temperatures ofthe refrigerator compartment 12 and the freezer compartment 13, and mayalso the present operating function. And the second screen 612 maydisplay the temperature of one storage space of the refrigeratorcompartment 12 or the freezer compartment 13 and the present operatingfunction in the corresponding storage space.

Meanwhile, when the sub-door 50 is closed, the display 61 detectsclosing of the sub-door 50 by the door switch 21, and the main controlpart 2 turns off the display 61.

FIG. 48 is a view illustrating the change in the display state of thedisplay unit when an auto-door function is set.

As illustrated in the drawing, in a state in which the sub-door 50 isopened and the display 61 is turned on, when the user pushes theauto-door button 623, the display 61 displays a third screen 613 whichindicates an activated state of the door opening device 70 when the dooropening device 70 is activated. And when the door opening device 70 isnot activated, the display 61 displays a fourth screen 614 whichindicates an inactivated state of the door opening device 70.

And when the user operates again the auto-door button 623 while thedisplay 61 displays the third screen 613 or the fourth screen 614, thethird screen 613 and the fourth screen 614 may be converted to eachother, and a state of the door opening device 70 may also besubstantially changed.

That is, when it is intended that the user does not use the door openingdevice 70, it may be set through operating of the auto-door button 623.And in this state, an operation of the door opening device 70 is notperformed.

Meanwhile, when the user's operation is not applied for a preset time ormore in a state in which it is converted to the third screen 613 or thefourth screen 614, the display 61 is converted to the first screen 611or the second screen 612 which indicates the temperature in therefrigerator 1. At this time, when the door opening device 70 isactivated, the auto-door button 623 may be in an ON state, and when thedoor opening device 70 is inactivated, the auto-door button 623 may bein an OFF state.

FIG. 49 is a view illustrating the change in the display state of thedisplay unit when an auto-drawer function is set.

As illustrated in the drawing, when the user pushes the auto-drawerbutton 624 while the sub-door 50 is opened and the display 61 is turnedon, the display 61 displays a fifth screen 615 which indicates anactivated state of the accommodation member withdrawing device 34 whenthe accommodation member withdrawing device 34 is activated. And whenthe accommodation member withdrawing device 34 is inactivated, thedisplay 61 displays a sixth screen 616 which indicates an inactivatedstate of the accommodation member withdrawing device 34.

And when the user operates again the auto-drawer button 624 while thedisplay 61 displays the fifth screen 615 or the sixth screen 616, thefifth screen 615 or the sixth screen 616 may be converted to each other,and a state of the accommodation member withdrawing device 34 may alsobe substantially changed.

That is, when it is intended that the user does not use theaccommodation member withdrawing device 34, it may be set throughoperating of the auto-drawer button 624. And in this state, an operationof the accommodation member withdrawing device 34 is not performed.

Meanwhile, when the user's operation is not applied for a preset time ormore in a state in which it is converted to the fifth screen 615 or thesixth screen 616, the display 61 is converted to the first screen 611 orthe second screen 612 which indicates the temperature in therefrigerator 1. At this time, when the accommodation member withdrawingdevice 34 is activated, the auto-drawer button 624 may be in an ONstate, and when the accommodation member withdrawing device 34 isinactivated, the auto-drawer button 624 may be in an OFF state.

FIG. 50 is a view illustrating the change in the display state of thedisplay unit when the temperature fixing function is set.

As illustrated in the drawing, in a state in which the sub-door 50 isopened and the display 61 is turned on, when the user pushes therefrigerator compartment temperature fixing button 625, the main controlpart 2 may control the operation of the refrigerator 1 so that thetemperature in the refrigerator 1 is maintained at a preset temperature,and a seventh screen 617 which indicates such a state is displayed. Andwhen a refrigerator compartment temperature fixing mode is not set, thedisplay 61 displays an eighth screen 618 which indicates an in activatedstate of the refrigerator compartment temperature fixing mode.

And when the user operates again the refrigerator compartmenttemperature fixing button 625 while the display 61 displays the seventhscreen 617 or the eighth screen 618, the seventh screen 617 or theeighth screen 618 may be converted to each other, and an operation modeof the refrigerator 1 may also be substantially changed.

That is, when it is intended that the user does not use the refrigeratorcompartment temperature fixing mode, it may be set through operating ofthe refrigerator compartment temperature fixing button 625. And in thisstate, an operation of the refrigerator compartment temperature fixingmode is not performed.

Meanwhile, when the user's operation is not applied for a preset time ormore in a state in which it is converted to the seventh screen 617 orthe eighth screen 618, the display 61 is converted to the first screen611 or the second screen 612 which indicates the temperature in therefrigerator 1. At this time, when the refrigerator compartmenttemperature fixing mode is activated, the refrigerator compartmenttemperature fixing button 625 may be in an ON state, and when therefrigerator compartment temperature fixing mode is inactivated, therefrigerator compartment temperature fixing button 625 may be in an OFFstate.

Also, in an operation of the freezer compartment temperature fixingbutton 626, the air cleaning button 627, the quick freezing button 628and the communication button 621, a state of the display 61 is changedin the above-described manner, except contents of the screen, and thusdetailed description thereof will be omitted.

The refrigerator and the control method thereof according to theproposed embodiment of the present invention have the following effects.

In the refrigerator according to the embodiment of the presentinvention, the panel assembly which selectively transmits or reflectsthe light is provided at a part of the door, and the lighting unit whichis turned on or off by the user's operation is provided inside the door,and the lighting unit can be turned on by the user's operation while thedoor is closed, and thus it is possible to see through the inside of therefrigerator.

Therefore, even while the door is not opened, the user can confirm thespace inside the refrigerator, and also can check the position of thefood, and thus the user convenience can be enhanced. Also, the door canbe prevented from being unnecessarily opened and closed, and loss of thecooling air can be prevented, and thus it is possible to improve powerconsumption and also to enhance storage performance.

And the panel assembly has a structure like a half glass which is seenthrough while the lighting unit is turned on, and functions as a mirrorwhile the lighting unit is not turned on, and thus an exterior of therefrigerator door can be enhanced.

And the microphone which detects a sound generated by the vibration uponthe user's knocking operation on the panel assembly can be provided atthe rear surface of the panel assembly. Therefore, the lighting unit canbe turned on or off by the user's knocking operation, and thus the panelassembly can be selectively transparent.

Therefore, since the panel assembly can become transparent by the simpleoperation, and the sound of the vibration transmitted through the samemedium is the same even though the user knocks on any positions of thefront surface of the panel assembly, the operation can be easilyperformed, and effectively detected.

Also, the microphone module having the built-in microphone of the knockdetection device is in close contact with the rear surface of the panelassembly, and thus a detection rate can be enhanced. At this point, thevibration or the sound wave having a certain wavelength generated uponthe knocking on the panel assembly is recognized as the valid signal,and thus the misrecognition due to an abnormal noise like the externalnoise is prevented.

And the detection device PCB which determines the knock signal isdisposed together with the knock detection device, and determines thevalid knock signal, and transmits a determined result to the maincontrol part inside the cabinet, and thus the efficiency and reliabilityin processing the signal can be enhanced by minimizing noise upon thedetermination of the knock signal. Also, when the signal input from theknock detection device is detected several times within the preset time,the signal is determined as the valid signal, and thus reliability ofthe operation can be further enhanced.

And the panel assembly includes the front panel formed of the halfmirror material, and the plurality of insulation panels formed of theinsulation glass, and thus thermal loss through the panel assembly canbe prevented. And the spacer bar and the sealant seals between the frontpanel and the insulation panel and between the plurality of insulationpanels, and thus an insulation space is formed, and the insulation spaceis in a vacuum state, or filled with an inert gas, and thus insulationperformance can be further enhanced.

And since the bezel is formed at the front panel, and the knockdetection device is located on the bezel, the knocking operation on thefront panel can be easily recognized, and the knock detection device isprevented from being exposed to an outside, and thus an exterior can befurther improved. Also, the detection device is formed at the bezelprovided at the lower end of the front panel, and thus the bezelprovided at another portion of the front panel can be relatively thin,and thus a see-through portion of the door can be widened.

And the foaming solution injection port for forming the insulation isformed at the lower end of the door, and the first foaming solutioninjection port is formed at a position of the second side frame having arelatively wide width so that the foaming solution can be directlyinjected toward the second side frame. And since a distance between thefirst side frame and the panel assembly is very narrow, and thus thefoaming solution may overflow, the second foaming solution injectionport is formed so that the foaming solution is injected toward an insidefurther than a position of the first side frame, i.e., the lower end ofthe panel assembly. Therefore, the foaming solution can be smoothlyinjected, and also can be prevented from being incompletely filled oroverflowing, and thus the insulation performance can be maintained.

And the side decoration which is in contact with the front plate isformed of the metallic material such as aluminum having high thermalconductivity. The heater installation part in which the sub-door heateris installed to be in contact with the outer end of the front plate isformed at the side decoration.

Therefore, the surface temperature of the front panel at the outerportion of the spacer bar which is vulnerable to dew condensation isincreased, and thus the dew condensation can be prevented. Also, sincethe front bent part is formed at the side decoration, and is in closecontact with the front panel, the dew condensation can be prevented frombeing generated along the perimeter of the front panel.

And since the knock detection device, the second detection device whichdetects the user's approach, and the detection device PCB areaccommodated and installed at the detection device accommodation partformed to be recessed at the lower end of the door, installation,assembling and maintenance of the detection device can be easilyperformed.

And the sub-door which can be seen through is accommodated inside theopening part of the main door, and the upper hinge and the lower hingeextend laterally, and pass through the hinge hole of the opening part,and are rotatably installed therein.

Therefore, an interference space due to the upper hinge and the lowerhinge can be prevented, and the sagging of the sub-door can also beprevented, and a gap between the opening part of the main door and thesub-door can be minimized, and thus the external appearance can beenhanced. Also, the side supporter which supports the upper hinge andthe lower hinge is formed of the metallic material, coupled to the upperhinge and the lower hinge so that the installation position thereof ismaintained, and thus the interference with the opening part due todeformation of the sub-door can be prevented.

The side supporter formed of the metallic material serves to maintain ashape of the sub-door at both ends of the sub-door, and also enhancesthe strength of the sub-door.

And the magnet is provided at a position at which the main door facesthe sub-door, and the attraction is formed between the main door and thesub-door, and thus while the sub-door is closed, the sub-door can bemaintained in the closed state by the magnetic force.

Therefore, the sub-door can be prevented from being unintentionallyopened due to a shock generated when the main door is closed and openedor an inertial force generated when the main door is rotated, and alsoloss of the cooling air and an increase in the power consumption can beprevented.

Even though all the elements of the embodiments are coupled into one oroperated in the combined state, the present disclosure is not limited tosuch an embodiment. That is, all the elements may be selectivelycombined with each other without departing from the scope of theinvention. Furthermore, when it is described that one comprises (orincludes or has) some elements, it should be understood that it maycomprise (or include or have) only those elements, or it may comprise(or include or have) other elements as well as those elements if thereis no specific limitation. Unless otherwise specifically defined herein,all terms comprising technical or scientific terms are to be givenmeanings understood by those skilled in the art. Like terms defined indictionaries, generally used terms needs to be construed as meaning usedin technical contexts and are not construed as ideal or excessivelyformal meanings unless otherwise clearly defined herein.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it will be understood by those skilledin the art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the invention as definedby the appended claims. Therefore, the preferred embodiments should beconsidered in a descriptive sense only and not for purposes oflimitation, and also the technical scope of the invention is not limitedto the embodiments. Furthermore, the present invention is defined not bythe detailed description of the invention but by the appended claims,and all differences within the scope will be construed as beingcomprised in the present disclosure.

INDUSTRIAL APPLICABILITY

According to embodiments, use convenience is improved, thereby achievinghigh industrial applicability.

1-10. (canceled)
 11. A refrigerator comprising: a cabinet configured toform a storage space; a door configured to open and close the cabinet,and rotatably connected to the cabinet by a hinge, the door including anouter plate, a door liner connected to the outer plate and an opening; apanel assembly configured to cover the opening, the panel assemblyincluding a front panel, a rear panel spaced apart from a rear surfaceof the front panel, and a spacer provided between the front panel andthe rear panel, wherein the front panel has a size greater than that ofthe rear panel and includes an viewing area and a bezel area disposedoutside the viewing area; a sensor disposed at the bezel area of thefront panel; and an electric wire electrically connected to the sensorand a controller.
 12. The refrigerator of claim 11, wherein the electricwire extends along an outer periphery of the panel assembly.
 13. Therefrigerator of claim 11, further comprising a lighting unit provided inthe inner space and to illuminate an inside of the refrigerator, whereinbased on the sensor detecting a user input signal applied on the frontpanel, the lighting unit is turned on such that an interior of thestorage space is visible through the viewing area of the front panelwhen the lighting unit is turned on in a state in which the door closesthe storage space.
 14. The refrigerator of claim 13, further comprisinga display unit configured to display an operation state of therefrigerator, wherein the display unit is disposed behind the rearpanel.
 15. The refrigerator of claim 14, wherein the display unit isdisposed in the opening of the main door.
 16. The refrigerator of claim13, wherein the display unit is turned on, based on the sensor detectingthe user input signal applied on the front panel.
 17. The refrigeratorof claim 11, wherein the sensor is provided closer to a boundary betweenthe viewing area and the bezel area than an outer edge of the frontpanel.
 18. The refrigerator of claim 11, further comprising a sub doorrotatable with respect to the cabinet, and a second hinge connected tothe sub door, wherein the sub door includes the panel assembly, and theelectric wire extends along the second hinge.
 19. A refrigeratorcomprising: a cabinet defining an inner space; a first door to open andclose the inner space and connected to the cabinet by a first hinge, andincluding a first frame that has a first opening; a second door to openand close the first opening, and including a second frame that has asecond opening and a panel assembly to cover the second opening; and asecond hinge connected to the second door, wherein the panel assemblyincludes: a front panel, a rear panel spaced apart from a rear surfaceof the front panel, and a spacer provided between the front panel andthe rear panel, wherein the front panel has a size greater than that ofthe rear panel and includes an viewing area and a bezel area disposedoutside the viewing area; a sensor disposed at the bezel area of thefront panel; and an electric wire electrically connected to the sensorand a controller, wherein the electric wire extends toward the firstdoor via the second hinge.
 20. The refrigerator of claim 19, wherein thesecond door further comprising a cap decoration the forms an upper or alower side of the second door to receive the sensor.
 21. Therefrigerator of claim 19, wherein the second frame comprises an electricwire guide part to guide the electric wire toward the second hinge. 22.The refrigerator of claim 21, wherein the second door further comprisinga hinge cover which shields at least a portion of the second hinge, andwherein the electric wire extends along a space between the second hingeand the hinge cover.
 23. The refrigerator of claim 19, furthercomprising a display unit configured to display an operation state ofthe refrigerator, wherein the display unit is disposed behind the rearpanel.
 24. The refrigerator of claim 23, wherein the display unit isdisposed in the first door.
 25. The refrigerator of claim 19, whereinthe display unit is turned on, based on the sensor detecting the userinput signal applied on the front panel.